From intelbalaji at yahoo.com Mon May 2 08:28:00 2011 From: intelbalaji at yahoo.com (Balaji Venkateshwaran) Date: Mon, 2 May 2011 08:28:00 -0700 (PDT) Subject: Early-stage startup opportunity Message-ID: <560333.43080.qm@web130101.mail.mud.yahoo.com> Dear SNF Labmembers - I recently received an inquiry from a top-tier investor looking for a specific skillset related to silicon process technology for one of his early-stage startups. I thought I would pass it on in case it fits any of you. Here is the description I have, its rather brief given the stealth and very early-stage nature of the startup. Let me know if you or anyone you know is interested (and why you would be a good fit) and I can forward the candidate to this investor for further discussions. Best regards, Balaji ----------------------------------------------------------- Lead the research activities in the field of oxide materials.? Candidate should have experience working with thin film insulator materials such as oxides in high fields.? Strong understanding of high fields in SiO2, local fields, defect chemistry of SiO2, failure mechanism, leakage current, interface effects, impurities.? Experience in CMOS and thin-film SiO2 structures, either modeling or experiment is required.? PhD in Materials Science, Physics, Applied Physics, or EE. ------------------------------------------------------------ -------------- next part -------------- An HTML attachment was scrubbed... URL: From mtang at stanford.edu Mon May 2 09:34:09 2011 From: mtang at stanford.edu (Mary Tang) Date: Mon, 02 May 2011 09:34:09 -0700 Subject: Seminar: Surface Wave Optomechanical Sensors, Dr. Gaurav Bahl Message-ID: <4DBEDD01.9060508@stanford.edu> Dear labmembers -- Dr. Gaurav Bahl is making a return visit to sunny Palo Alto to talk about the work he is doing at the University of Michigan. Prof. Howe is hosting this seminar today at 4 pm in the Allen 101X auditorium. Details are attached. M -- Mary X. Tang, Ph.D. Stanford Nanofabrication Facility Paul G. Allen Room 136, Mail Code 4070 Stanford, CA 94305 (650)723-9980 mtang at stanford.edu http://snf.stanford.edu -------------- next part -------------- A non-text attachment was scrubbed... Name: 2011_05_02 GB MEMS Talk.pdf Type: application/pdf Size: 394086 bytes Desc: not available URL: From mtang at stanford.edu Mon May 2 09:40:04 2011 From: mtang at stanford.edu (Mary Tang) Date: Mon, 02 May 2011 09:40:04 -0700 Subject: Process Clinic today - CANCELED Message-ID: <4DBEDE64.2020700@stanford.edu> Apologies, but the process clinic normally scheduled this afternoon has been canceled. Next one is in two weeks. If you have pressing process questions or issues, please get in touch with any process staff member. Cheers -- M -- Mary X. Tang, Ph.D. Stanford Nanofabrication Facility Paul G. Allen Room 136, Mail Code 4070 Stanford, CA 94305 (650)723-9980 mtang at stanford.edu http://snf.stanford.edu From cachang at stanford.edu Mon May 2 11:03:38 2011 From: cachang at stanford.edu (Chia-Ming Chang) Date: Mon, 2 May 2011 11:03:38 -0700 (PDT) Subject: [Reminder] Special Seminar - Dr. Corsin Battaglia (EPFL), Tuesday May 03, 2:15PM, Astrophysics 102/103 In-Reply-To: <389013633.27062.1303769943177.JavaMail.root@zm06.stanford.edu> Message-ID: <501980227.236224.1304359418182.JavaMail.root@zm06.stanford.edu> Prnom NOM Special Seminar Presented by the Stanford Optical Society Light trapping for high-efficiency thin-film silicon solar cells Dr. Corsin Battaglia Institute of Microengineering, EPFL Tuesday, May 03, 2:15 PM, Astrophysics 102/103 Refreshments at 2PM Thin-film silicon solar cells have been identified as one of the most promising technologies to render photovoltaics, the conversion of sunlight to electricity, economically competitive with fossil-fuel technologies, as they are based on abundant, non-toxic materials and low-temperature processes. Advanced light trapping concepts are crucial to realize high-efficiency thin-film silicon solar cells, as the absorption coefficient of silicon is small in the near-infrared region. With properly engineered photonic nanostructures, sunlight can be trapped within the thin absorbing silicon layers, thereby enhancing light absorption and thus conversion efficiencies. We present here the latest research developments in single-junction amorphous and tandem micromorph (amorphous/microcrystalline) silicon solar cells in our laboratory. Recently developed nanocrystalline silicon oxide layers [1, 2], deposited by plasma-enhanced chemical vapor deposition, enable the integration of photonic nanostructures until now considered too aggressive to maintain acceptable electrical cell performance. In combination with the optimized random pyramidal morphology of transparent conductive zinc oxide films, grown by chemical vapor deposition, outstanding light trapping capabilities are demonstrated [3] which have lead to several certified world record conversion efficiencies [4, 5]. To implement arbitrarily designed surface morphologies directly into functional cells, we recently fabricated transparent nanotextured front electrodes by ultraviolet nanoimprint lithography [6] and demonstrated cell efficiencies as high as for state-of-the-art zinc oxide electrodes [7]. We further present an innovative new method [8] allowing one to impose an arbitrary surface morphology onto transparent conductive zinc oxide films providing a versatile experimental platform in the quest to find the most efficient light harvesting scheme. About the speaker Corsin BATTAGLIA obtained his PhD in physics from the University of Neuch?tel, Switzerland in 2008 for his work on the structural and electronic properties of self-assembled nanostructures on silicon surfaces. He also worked at Hitachi, Japan and at the Paul Scherrer Institute, Switzerland. In 2009, he joined EPFL?s PV-Lab, Switzerland as a postdoc and project leader where he works on advanced light management concepts for thin-film silicon solar cells ranging from the development of new substrates and electrode materials to the fabrication and characterization of complete cells. [1] M. Despeisse et al, Appl. Phys. Lett. (2010) [2] P. Cuony et al, Appl. Phys. Lett. (2010) [3] M. Despeisse et al, Phys. Stat. Solidi a (2011) [4] S. Benagli et al, Proc. 24th European Photovoltaic Energy Conference, Hamburg (2009) [5] J. Bailat et al, Proc. 5th World Conference on Photovoltaic Energy Conversion, Valencia (2010) [6] C. Battaglia et al, Appl. Phys. Lett. (2010) [7] C. Battaglia et al, Nano Letters (2011) [8] C. Battaglia et al, submitted (2011) http://photons.stanford.edu -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: Seminar_Battaglia.pdf Type: application/pdf Size: 29532 bytes Desc: not available URL: From vijayp at stanford.edu Mon May 2 17:53:16 2011 From: vijayp at stanford.edu (Vijay Parameshwaran) Date: Mon, 2 May 2011 17:53:16 -0700 (PDT) Subject: Silicon <111> wafers In-Reply-To: <194764408.923283.1304381677560.JavaMail.root@zm02.stanford.edu> Message-ID: <1502538053.924512.1304383996363.JavaMail.root@zm02.stanford.edu> Hi SNF people, Does anyone have a silicon <111> wafer that I can have? Thanks, Vijay Parameshwaran vijayp at stanford.edu From mbaran at stanford.edu Tue May 3 15:06:20 2011 From: mbaran at stanford.edu (Maureen Baran) Date: Tue, 3 May 2011 15:06:20 -0700 Subject: Car Keys Found on the First Floor of the Allen Building Message-ID: <009401cc09de$553aac40$ffb004c0$@edu> Dear All, A concerned lab member and Allen building Dweller found a Ford car key and fob on the couch across from the Industry Day Use cubicles. If it's yours please come by my cubicle # 41 and pick it up. Maureen Maureen Baran Stanford Nanofabrication Facility Lab Services Administrator mbaran at stanford.edu 650-725-3664 -------------- next part -------------- An HTML attachment was scrubbed... URL: From chingmei at stanford.edu Wed May 4 16:07:43 2011 From: chingmei at stanford.edu (Ching-Mei Hsu) Date: Wed, 4 May 2011 16:07:43 -0700 Subject: PhD Oral Examination: Ching-Mei Hsu (Thursday, May 5th, 10:00am) In-Reply-To: References: Message-ID: *Photon Management for a-Si:H Solar Cells Using Periodic Nanostructures ** Ching-Mei Hsu* * * Department of Materials Science and Engineering Advisor: Prof. Yi Cui Thursday May 5th 2011, 10:00 am (Refreshments at 9:45 am) Location: Paul G. Allen Auditorium (CIS-X 101) http://cis.stanford.edu/misc/directions.html Solar technology is a leading candidate for clean energy production. Silicon is an excellent material for photovoltaic (PV) applications due to its low toxicity, abundance, long term stability, and well developed processing technologies. Crystalline Si solar cells currently dominate the photovoltaic market despite requiring more material and more energy-intensive manufacturing processes than their thin-film counterparts. Thin-film silicon, e.g. amorphous silicon (a-Si:H), provides the advantage of decreasing material costs over crystalline silicon. Because the material is amorphous, there are many defects, which results in a small minority carrier diffusion length. Thus, a thinner absorber is required. However, thinner absorber layers do not absorb light effectively, resulting in poor cell performance. If the active material could be made to absorb all of the light in a film with a thickness approximately equal to the minority carrier diffusion length, the open-circuit voltage (Voc), short-circuit current (Jsc), and fill factor (FF) of the device would be greater than those of a thicker cell. My research is comprised of three parts: (1) developing a nanostructure fabrication process, (2) designing device geometries for alternative light trapping strategies in both substrate and superstrate configurations, and (3) investigating the effects of nanostructures? morphologies on the optical and electrical properties of devices. In contrast to the use of randomized surface texturing to improve the coupling of light into the active material, we employed periodic nanostructures to couple incident light into guided modes that propagate in the plane of the absorber. This approach can significantly increase the optical path length inside a thin absorber layer. To achieve this goal, I first developed a nanostructure fabrication process by combining self-assembly and reactive ion etching. We then employ these as-made nanostructures in a-Si:H solar cells. The periodic-nanostructure devices show an enhanced absorption and photocurrent generation in comparison with planar cells. We used FTDT studies to confirm that the increased photocurrent was indeed caused by enhanced absorption. We also systematically studied the effects of morphological parameters on light-trapping efficiency and electrical characteristics of the device. With my optical and electrical findings, we have achieved efficiencies up to 9.7% for devices with substrate configurations and 10.2 % for devices with superstrate configurations. -- Ching-Mei Hsu PhD Candidate Stanford University Materials Science and Engineering 476 Lomita Mall, McCullough Bld. Rm 217 Stanford, CA 94305 email: chingmei at stanford.edu ; chingmei1219 at gmail.com -------------- next part -------------- An HTML attachment was scrubbed... URL: From shott at stanford.edu Thu May 5 09:48:30 2011 From: shott at stanford.edu (John Shott) Date: Thu, 05 May 2011 09:48:30 -0700 Subject: Disk usage on the sunrays .... Message-ID: <4DC2D4DE.3020007@stanford.edu> SNF Lab Members: The disks on the sunrays are full again. This causes everything to screech to a halt and you think that Coral is dead. Coral is not dead! The disks are full! This machine is not designed for file storage and there is way too much usage. Following in decreasing order are the users that are using more that 100 MB of disk space. We need to make some big gains by deleting some big files or this problem will simply return. Please help, John 898212 jwc 549127 maurice 499660 mdickey 462177 sbiaa 419689 mtan 415125 chen0622 389045 hktran 379113 vossough 378780 gunjim 366216 suyog 350855 eenriquez 343290 jtsai 338853 mvikram 337839 lyjiao 333580 pnataraj 330980 rostam 324741 naiqian 302003 romana 292047 cbellew 283589 mislam 283399 insun 278094 khoang 266297 bchui 258345 megrubbs 258294 popomoo 250243 kosarb 249710 king 233702 cmfaulkn 231991 chongxie 227288 calarrudo 224630 svo 222289 gyama 214304 mcvittie 210754 zpatel 206556 liangjl 205018 rparsa 197962 nppatil 196863 renshen 195717 takuyan 194228 ywidjaja 192356 mrlin 183820 dkozak 181201 daesung 181058 hopcroft 179981 ybkim 179969 cbaxter 178459 ryw 175556 wanki 174814 junil 171858 ocakkaya 168281 ghyrn 167678 dxu 166899 altug 165993 gth 163865 axiu 161021 pponce 160414 jasonlin 159019 jperez 158387 hrleebh 158038 faridz 157567 chienyuc 157190 yoavb 156104 dalyx 155295 gerke 154728 cursive 152729 junjun 152636 aeonia 152426 jsnapp 152118 jfoster 151904 dasgupta 151430 sdogbe 151208 jjeong1 150049 djwong 149887 alsune 148738 jhaydon 148634 jennyhu 146165 nharjee 143977 haiwei 143924 dongrip 142908 oisaadat 141983 fanpy 141970 jleu 141954 kghadiri 141536 sipark 141448 kokab 138751 ericp 138588 fpurkl 138577 srikantv 136600 erichall 136573 zzp 136542 ahazeghi 135831 dniemann 134656 mcherry 134361 alexneu 133526 lindaw 133487 kcbalram 133346 ludwig 132991 ajamo 132366 mihirt 131732 haniff 131203 yoonjin 130328 swalker 129460 masaharu 128750 kimsangb 128662 rrick 126825 muchiao 126442 xzhuan1 125978 elibol 125224 mkseo 124388 solorzan 124387 fanzeng 123591 fatihs 123472 dpb167 123120 iwjung 122553 barlian 122125 cdietz 122062 pbrink 122030 okilic 121232 dgunning 120884 ginel 120579 takane 120535 rshyam 118982 kattsai 118893 jcdoll 118848 mnakamura 118769 grupp 118150 yiwu 116720 damodei 116523 ylinn 116441 uli 115966 yanyao 114926 maryamzm 114902 skoh 114683 yiyang 114405 lwchang 114404 dfulgencio 113944 ayz 113260 malekos 112745 oliversw 112466 evander 112420 grahamab 111990 me342e 111981 yinliu 111960 bdai 111956 jeh0513 111569 kupnik 111487 jackson 111405 awu 110904 cchen86 110760 johana 110665 flannery 110646 asanders4 110479 latta 109620 cmcg 109595 kasliwal 109458 mcp 109309 rlalley 108804 amet 108573 nuernberg 108496 laurahughes 108195 wangss 107625 patlu 107562 karthikv 107385 zeyuan 107231 whlee 107202 me342d 106834 marklee 106056 leohuang 105957 ee410d 105918 wslee 105703 clu 105628 ytcheng 105381 jnhagemeier 105200 fungus 105186 spaik1 105153 isagiv 105130 mtang 105048 vishal 104772 clifton 104595 show 104584 shuluc 104406 jgantz 104401 brake2002 104278 eward 103974 krivoire 103645 cfchiang 103208 mwolfson 102971 yhngchen 102499 mferrier 102175 qtang 101992 jpadovani 101444 dhelqaq 101243 rhenn 101184 ycjun 101090 mattm3 100547 fteng 100439 kavehm 100403 ysohn 100106 tantawi From jprovine at stanford.edu Sat May 7 09:28:09 2011 From: jprovine at stanford.edu (J Provine) Date: Sat, 7 May 2011 09:28:09 -0700 Subject: Smell in the fab Message-ID: A strong smell of photoresist (mixed with a bit of a developer smell also) is permeating the lab. It is strong in the litho area but detectable in the white area and the gowning room as well. Please be aware. Current fab users can not trace the source of the smell. Signs will be posted at the litho entrance doors to warn of the smell and the staff phone was called and they will investigate further as soon as possible. J From gsosa at stanford.edu Sat May 7 16:45:16 2011 From: gsosa at stanford.edu (Gary J Sosa) Date: Sat, 7 May 2011 16:45:16 -0700 (PDT) Subject: Smell in the fab In-Reply-To: Message-ID: <1449951922.7840.1304811916836.JavaMail.root@zm08.stanford.edu> Hello Lab-members.... Just following up on the reported smell in the fab. At about 1:30 PM, did a thorough investigation of the Litho area for spill and leaks in and around all tools. Also checked all hazardous waste and regular waste cans- All OK. All tool and wet bench exhausts working fine. Could not find any obvious reason for the odor. I noticed when I got here that there was a solvent type odor outside of the building. I could also smell it in the main hallway and the change room and in litho but to a lesser degree. 2 other users also smelled something outside. Possibly something going on at the Cogen plant and getting pulled in by our air handlers. Left for a while and returned and checked the Litho area out between 4 and 4:30 PM. Could not detect any more odor. Suspect that the source of the smell was coming from outside. Please continue to be aware of and report any unusual odors in the lab. If there is a re-occurrence of the odor, please do not hesitate to call the SNF Staff cell phone at 650-521-7306 and leave the area if necessary as a health and safety precaution. Thanks... Your SNF Staff ----- Original Message ----- From: "J Provine" To: labmembers at snf.stanford.edu Sent: Saturday, May 7, 2011 9:28:09 AM Subject: Smell in the fab A strong smell of photoresist (mixed with a bit of a developer smell also) is permeating the lab. It is strong in the litho area but detectable in the white area and the gowning room as well. Please be aware. Current fab users can not trace the source of the smell. Signs will be posted at the litho entrance doors to warn of the smell and the staff phone was called and they will investigate further as soon as possible. J From npapte at stanford.edu Sun May 8 10:14:08 2011 From: npapte at stanford.edu (Nikhil Apte) Date: Sun, 8 May 2011 10:14:08 -0700 Subject: debonding resist bonded wafers Message-ID: Hello labmembers, I am trying to debond two wafers which were resist-bonded using 7um thick SPR 220-7 resist. So far I have tried 1165 solvent at room temperature for over 48 hours, PRS-1000 at 40C for 2 hours, 1165 solvent heated to 80 C for 1 hour, as well as acetone at room temperature for 1 hour. However the wafers still haven't debonded. I cannot use piranha solution as this wafer has metal on it. Could anyone suggest me what I should use to debond these wafers, and how long does it usually take. Thanks, Nikhil -------------- next part -------------- An HTML attachment was scrubbed... URL: From shott at stanford.edu Mon May 9 08:24:19 2011 From: shott at stanford.edu (John Shott) Date: Mon, 09 May 2011 08:24:19 -0700 Subject: Ginzton Demolition Update ... Message-ID: <4DC80723.8040805@stanford.edu> SNF Lab Members: This week there will be demolition of the foundation of the Ginzton building that may affect vibration-sensitive tools such as the Raith and SEM inspection tools. According to the general contractor (Whiting-Turner) on Monday and Friday of this week, the jack hammering activity should occur between 6 a.m. and 9 a.m. On Tuesday, Wednesday, and Thursday that activity should be confined to 6 a.m. to 8 a.m. We hope that these activities will not be overly disruptive. Thanks, John From ybkim at stanford.edu Mon May 9 10:31:40 2011 From: ybkim at stanford.edu (Young-Beom Kim) Date: Mon, 9 May 2011 10:31:40 -0700 (PDT) Subject: ME PhD Oral Examination: Young Beom Kim (Friday, May 13th, 10:00am) In-Reply-To: <1686214285.37996.1304962046274.JavaMail.root@zm02.stanford.edu> Message-ID: <686229162.38217.1304962300938.JavaMail.root@zm02.stanford.edu> ???????????????????????????????????????????????????????????????????????????????????????????? Stanford University Ph.D. Dissertation Defense? ?????????????????????????????????????????????????????????????????????? Title: ?Nanoscale Engineering for Low-Temperature Ceramic Fuel Cells?? ???????????????????????????????????????????????????????????????????????????????????????????????????????????????Young Beom Kim ? ?????????????????????????????????????????????????????????????????????????????????????????????????Department of Mechanical Engineering? ????????????????????????????????????????????????????????????????????????????????????????????????????????Advisor: ?Prof. Fritz B. Prinz? ???????????????????????????????????????????????????????????????????????????????????????????????????????Date: ?Friday, May 13th, 2011? ?????????????????????????????????????????????????????????????????????????????????????????????Time: 10:00am (Refreshments at 9:45am)? ????????????????????????????????????????????????????????????????????????????????Location: Mitchell Earth Science (Hartley Conference Room)? ?????????????????????????????????????????????????????????????????????????????????????? http://campus-map.stanford.edu/index.cfm?ID=04-560?? Solid oxide fuel cells (SOFCs) have been under intense investigation for their high energy conversion efficiency and their use in various practical applications. However, due to the high activation energy of ion transport through the solid electrolyte (ohmic loss) and the sluggish oxygen reduction reaction at the cathode side (activation loss), they have usually been operated at a relatively high temperature range (800-1000oC). This high operating temperature poses serious challenges for widespread applications in terms of compatibility of fuel cell components, seal integrity, and structural and thermal stability. For this reason, there have been numerous efforts to reduce the operating temperature to the lower regime (300-500oC, LT-SOFC). Unfortunately, lowering the operating temperature causes increase of the losses which previously mentioned. To compensate for the increased ohmic resistance due to slow ionic transport through the YSZ layer at low temperature, we developed thin film techniques such as PLD and ALD to reduce the electrolyte thickness down to less than 100nm range and have succeeded at decreasing ohmic resistance. However, as the operating temperature is reduced, the activation loss, which mainly comes from the electrode polarization process at the cathode, still remains a key challenge. In this talk, three approaches are presented to improve LT-SOFC performance by reducing the activation loss. The first part is the actual electrochemical reaction site control and maximization. The triple phase boundary (TPB) is known as the actual reaction site for fuel cell charge transfer reaction. Nano-pore structured electrodes, which have stability and controllability, were fabricated to optimize and maximize the actual reaction site for performance enhancement. The second approach is to improve charge transfer reaction by adding a thin cathodic interlayer having superior catalytic activity on oxygen kinetics. Nanoscale yttria-doped ceria (YDC) cathodic interlayer was deposited on YSZ by using pulsed laser deposition (PLD) method and surface grain structure contribution on oxygen kinetics was investigated. The third part of the presentation is three-dimensional (3-D) fuel cell architecture fabrication by developing a new process. Increasing effective surface area is important to increase the power output for energy conversion devices. All these approaches and experimental results provide significant implications in designing the LT-SOFCs to improve the performance by reducing the activation loss. -- Young Beom Kim Ph.D. Candidate? Nanoscale Prototyping Laboratory for Energy Mechanical Engineering Stanford University 440 Escondido Mall, Bldg.530, Rm. 226 Stanford, CA 94305 -------------- next part -------------- An HTML attachment was scrubbed... URL: From hweiyin at stanford.edu Tue May 10 16:02:25 2011 From: hweiyin at stanford.edu (Serene Koh) Date: Tue, 10 May 2011 16:02:25 -0700 Subject: EE PhD Oral Examination - H.Y. Serene Koh, Friday May 13, 2011; 9:30 a.m. In-Reply-To: <533CBF45-D017-41FC-80EF-E560DFC9D336@stanford.edu> References: <533CBF45-D017-41FC-80EF-E560DFC9D336@stanford.edu> Message-ID: Stanford University Oral Defense - Department of Electrical Engineering Speaker: H. Y. Serene Koh Advisor: Prof. James D. Plummer Date: Friday, May 13, 2011 Time: 9.30am (Refreshments served at 9.15am) Location: Allen Auditorium (CIS-X Auditorium) Title: Rapid Melt Growth of Silicon Germanium Abstract: Silicon has made modern integrated circuit technology possible. As MOSFET gate lengths are scaled to 22nm and beyond, it has become apparent that new materials must be introduced to the silicon-based CMOS process for improved performance and functionality. This presentation first discusses Band-to-Band Tunneling (BTBT) transistors, which have the potential for steeper subthreshold slopes than conventional MOSFETs. It is clear that these devices must be fabricated in materials with smaller bandgaps for improved performance. SiGe is one possible material system that could be used to fabricate enhanced BTBT transistors. The development of process for obtaining SiGe-on-insulator from bulk Si substrates through Rapid Melt Growth (RMG) will be presented. RMG is a technique that has been used to recrystallize materials on Si substrates. RMG, however, has not previously been applied to SiGe, a binary alloy with large separation in the liquidus-solidus curve its phase diagram. I will present the experimental results, and explain and model the compositional profiles obtained during RMG of SiGe. The success of RMG SiGe suggests that the RMG technique can also be applied to III-V ternary and quaternary compounds with similar pseudo-binary phase diagrams, opening up a wide range of material possibilities with the potential for novel applications in heterogeneous integration and 3-D device technology. -------------- next part -------------- An HTML attachment was scrubbed... URL: From mtang at stanford.edu Tue May 10 18:09:45 2011 From: mtang at stanford.edu (Mary Tang) Date: Tue, 10 May 2011 18:09:45 -0700 Subject: Venture Clinic, 3 pm Wednesday, 5/11, Allen 101 Message-ID: <4DC9E1D9.9060603@stanford.edu> Dear labmembers -- Another Venture Clinic for anyone interested in learning about the venture business. Gavin McCraley from Morrison& Foerster and Shahin Farschi from Lux Capital will be on hand to talk about the business and answer your questions. The Venture clinic is Wednesday, 5/11 at 3 pm in the Allen 101 conference room and open to all. Contact info for the discussion leaders are: Shahin Farshchi, Ph.D. http://www.luxcapital.com C: 925.323.2784 and Gavin McCraley Morrison& Foerster LLP Direct: 650-813-4105 gmccraley at mofo.com -- Mary X. Tang, Ph.D. Stanford Nanofabrication Facility Paul G. Allen Room 136, Mail Code 4070 Stanford, CA 94305 (650)723-9980 mtang at stanford.edu http://snf.stanford.edu From chongxie at stanford.edu Tue May 10 21:19:27 2011 From: chongxie at stanford.edu (Chong Xie) Date: Tue, 10 May 2011 21:19:27 -0700 Subject: PhD Oral Examination: Chong Xie (Mon May 23, 10am, CISX 101) Message-ID: Nanopillars for cellular interface *Chong Xie* Department of Materials Science and Engineering Research Advisor: Professor Yi Cui and Professor Bianxiao Cui * May 23rd (Monday), 2011 @ 10:00 am * (Refreshments served at 9:45 am) Location :* CISX Auditorium (101X)* http://cis.stanford.edu/misc/directions.html The small scale of nano-materials make them one of the best man-made candidates to interact with biological systems at subcellular or even molecular level. It has been the focal point of the research interests to interfacing live cells with one dimensional nanostructures, such as nanowires and nanopillars. In this presentation, I will first introduce the general behavior of cell growth and functions in the presence of nanopillars, and then cover two topics of my PhD research: using this unique structure to interface cells both electrically and optically. 1. We achieve improved electric interface between biological cells and solid state device by using arrays of vertically aligned nanopillar electrodes. Their tight attachment to the cell membrane allows us to acquire intracellular-like action potential signals non-destructively from cultured cardiomyocytes, which is responsible for various important cellular functions. 2. We demonstrate below-the-diffraction-limit observation volume *in vitro* and inside live cells by using vertically aligned silicon dioxide nanopillars. With a diameter much smaller than the wavelength of visible light, a transparent silicon dioxide nanopillar embedded in a nontransparent substrate restricts the propagation of light and affords evanescence wave excitation along its vertical surface. This effect creates highly-confined illumination volume that selectively excites fluorescence molecules in the vicinity of the nanopillar. We show that this nanopillar illumination can be used for *in vitro* single molecule detection with high fluorescence background. In addition, we demonstrate that vertical nanopillars interface tightly with live cells and function as highly localized light sources inside the cell. Furthermore, chemical modification of the nanopillar surface provides a unique way to locally recruit proteins of interest and simultaneously observe their behavior within the complex, crowded environment of the cell. -------------- next part -------------- An HTML attachment was scrubbed... URL: From mtang at stanford.edu Wed May 11 13:46:45 2011 From: mtang at stanford.edu (Mary Tang) Date: Wed, 11 May 2011 13:46:45 -0700 Subject: Job posting from MIT Lincoln abs Message-ID: <4DCAF5B5.7010407@stanford.edu> Dear labmembers -- Prof. Howe has forwarded some job postings from MIT which may be of interest. M -------------- next part -------------- A non-text attachment was scrubbed... Name: ImageSensorDesigner_MITLL.pdf Type: application/octet-stream Size: 126287 bytes Desc: not available URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: ProcessDevelopmentScientist_MITLL.pdf Type: application/octet-stream Size: 124825 bytes Desc: not available URL: From ybkim at stanford.edu Thu May 12 12:57:25 2011 From: ybkim at stanford.edu (Young-Beom Kim) Date: Thu, 12 May 2011 12:57:25 -0700 (PDT) Subject: ME PhD Oral Examination: Young Beom Kim (Friday, May 13th, 10:00am) In-Reply-To: <686229162.38217.1304962300938.JavaMail.root@zm02.stanford.edu> Message-ID: <806802527.170346.1305230245210.JavaMail.root@zm02.stanford.edu> ???????????????????????????????????????????????????????????????????????????????????????????? Stanford University Ph.D. Dissertation Defense?? ?????????????????????????????????????????????????????????????????? Title: ?Nanoscale Engineering for Low-Temperature Ceramic Fuel Cells?? ???????????????????????????????????????????????????????????????????????????????????????????????????????????????Young Beom Kim ? ?????????????????????????????????????????????????????????????????????????????????????????????????Department of Mechanical Engineering? ????????????????????????????????????????????????????????????????????????????????????????????????????????Advisor: ?Prof. Fritz B. Prinz? ???????????????????????????????????????????????????????????????????????????????????????????????????????Date: ?Friday, May 13th, 2011? ?????????????????????????????????????????????????????????????????????????????????????????????Time: 10:00am (Refreshments at 9:45am)? ????????????????????????????????????????????????????????????????????????????????Location: Mitchell Earth Science (Hartley Conference Room)? ?????????????????????????????????????????????????????????????????????????????????????? http://campus-map.stanford.edu/index.cfm?ID=04-560?? Solid oxide fuel cells (SOFCs) have been under intense investigation for their high energy conversion efficiency and their use in various practical applications. However, due to the high activation energy of ion transport through the solid electrolyte (ohmic loss) and the sluggish oxygen reduction reaction at the cathode side (activation loss), they have usually been operated at a relatively high temperature range (800-1000oC). This high operating temperature poses serious challenges for widespread applications in terms of compatibility of fuel cell components, seal integrity, and structural and thermal stability. For this reason, there have been numerous efforts to reduce the operating temperature to the lower regime (300-500oC, LT-SOFC). Unfortunately, lowering the operating temperature causes increase of the losses which previously mentioned. To compensate for the increased ohmic resistance due to slow ionic transport through the YSZ layer at low temperature, we developed thin film techniques such as PLD and ALD to reduce the electrolyte thickness down to less than 100nm range and have succeeded at decreasing ohmic resistance. However, as the operating temperature is reduced, the activation loss, which mainly comes from the electrode polarization process at the cathode, still remains a key challenge. In this talk, three approaches are presented to improve LT-SOFC performance by reducing the activation loss. The first part is the actual electrochemical reaction site control and maximization. The triple phase boundary (TPB) is known as the actual reaction site for fuel cell charge transfer reaction. Nano-pore structured electrodes, which have stability and controllability, were fabricated to optimize and maximize the actual reaction site for performance enhancement. The second approach is to improve charge transfer reaction by adding a thin cathodic interlayer having superior catalytic activity on oxygen kinetics. Nanoscale yttria-doped ceria (YDC) cathodic interlayer was deposited on YSZ by using pulsed laser deposition (PLD) method and surface grain structure contribution on oxygen kinetics was investigated. The third part of the presentation is three-dimensional (3-D) fuel cell architecture fabrication by developing a new process. Increasing effective surface area is important to increase the power output for energy conversion devices. All these approaches and experimental results provide significant implications in designing the LT-SOFCs to improve the performance by reducing the activation loss. -- Young Beom Kim Ph.D. Candidate? Nanoscale Prototyping Laboratory for Energy Mechanical Engineering Stanford University 440 Escondido Mall, Bldg.530, Rm. 226 Stanford, CA 94305 -------------- next part -------------- An HTML attachment was scrubbed... URL: From wslee at stanford.edu Thu May 12 13:53:37 2011 From: wslee at stanford.edu (Scott Lee) Date: Thu, 12 May 2011 13:53:37 -0700 Subject: Polytec Seminar Message-ID: Hi all, There is a Polytec seminar next week in Milipitas for anyone interested in hearing about their latest research. Contact Eric directly if there are any questions. Cheers, Scott ---------- Forwarded message ---------- From: Eric Lawrence Date: Thu, May 12, 2011 at 10:20 AM Subject: Tech Seminar To: Scott Lee Scott, Hope everything is going well. We are having a Tech Seminar next week. Let me know if there is anyone interested from the SNF group. We have invited speakers showing their research, including Paul Cristman who is giving his presentation on Ultrasonic MEMS transducers. We showed you most of what we have for MEMS when we visited last February, but this might be interesting in terms of new developments and other applications (bio and ultrasonic). Best Regards, *Eric Lawrence* Northwest Territory Manager (714) 200 -4019 ** *Join us for **Polytec's Technology Seminar** in the Bay Area on May 18th. *** *Learn about our latest developments in Polytec's Technology.* *For more information, click here .* *From:* Scott Lee [mailto:wslee at stanford.edu] *Sent:* Tuesday, February 22, 2011 7:57 AM *To:* labmembers at snf.stanford.edu; howegroup at lists.stanford.edu; nems-logic *Cc:* Eric Lawrence *Subject:* Dynamic Characterization of MEMS Using Laser Vibrometry, TODAY @ 2PM On Tue, Feb 15, 2011 at 9:21 AM, Scott Lee wrote: Hi all, Next week, Eric Lawrence of Polytec will be demonstrating their latest laser vibrometry tools. If you have samples that you would like to characterize, let me know and we may be able to arrange it. Thanks, Scott * -------------------------------------------------------------------------------------------------------------------------- * *Technical Presentation: **Dynamic Characterization of MEMS using Laser Vibrometry* *When: *Tuesday February 22, 2:00 PM *Where: **Room *338X, PAUL G. ALLEN BUILDING (04-050), 420 VIA PALOU MALL * * ** * * Polytec presents technology for dynamic characterization of MEMS. OurMicro System Analyzer (MSA-500) combines powerful tools for analysis and visualization of structural vibrations of MEMS. The MSA-500 features laser vibrometry for measurement of out-of-plane motion with resolution down to * picometers* and bandwidth out to MHz. Scanning measurements provide full-field mapping and 3D visualization of deflection shapes. The system also includes Strobe Video Microscopy for planar motion and White Light Interferometer for static topography measurements. Our latest capabilities include our Ultra High Frequency (UHF-120) Vibrometer featuring 1.2 GHz frequency bandwidth. This technology is used throughout the MEMS research community. We present several characterization studies where our MSA has been instrumental in research and development of MEMS. *Our engineers will present new advances in our measurement technology and discuss potential MEMS applications you may have. * * * *More information at: http://www.polytec.com/int/applications/micro-nano-technology/* ** *Eric Lawrence* Northwest Territory Manager Polytec Inc. Irvine Technology Center 16400 Bake Parkway Irvine, CA 92618 Cell: (714) 200-4019 -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: image002.jpg Type: image/jpeg Size: 23027 bytes Desc: not available URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: image003.png Type: image/png Size: 7506 bytes Desc: not available URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: Agenda_Bay_Area_Tech_Seminar_May2011.pdf Type: application/octet-stream Size: 48755 bytes Desc: not available URL: From hyungkyu at stanford.edu Thu May 12 15:31:12 2011 From: hyungkyu at stanford.edu (hyungkyu lee) Date: Thu, 12 May 2011 15:31:12 -0700 Subject: ME PhD Oral Examination: Hyung Kyu Lee (Monday, May 16th, 2:00 pm) Message-ID: <6199CBBD-82EB-4F7F-99E0-ECE830BD555A@stanford.edu> Stanford University Ph.D. Dissertation Defense Title: ?Frequency Stability of Micromechanical Resonators with Nonlinearities? Hyung Kyu Lee Department of Mechanical Engineering Advisor: Prof. Thomas W. Kenny Date: Monday, May 16th, 2011 Time: 2:00 pm (Refreshments at 1:45 pm) Location: Mechanical Engineering Research Lab (MERL, bldg. 660), Conference room (203) http://campus-map.stanford.edu/index.cfm?ID=02-660 Abstract: Frequency references are an essential component of electronics, and there is increased interest in miniaturized frequency references. This interest has heightened the need for MEMS resonator-based oscillators because they can provide frequency references at low cost in small packages. Of particular interest is the oscillators' the temperature stability and the phase noise performance: temperature stability must be low enough for the resonator to provide a stable reference signal, and the frequency references in RF devices must satisfy stringent phase noise specifications. The first part of the presentation discusses the effect of nonlinearities in a resonator on the temperature stability of the resonator-based timing reference. To achieve good temperature stability , various temperature compensation techniques have been developed. Some of these compensation techniques tend to demonstrate resonator performance by using open-loop network analyzer measurements. However, most applications require a closed-loop system, with the resonator embedded in a feedback loop to form an oscillator. Thus, temperature stability measured in a closed-loop is more accurate for real-world applications. If the temperature stability decreases when the resonator is part of a closed-loop, it is very undesirable. In this part, I explain how this undesirable change commonly occurs, and I demonstrate how they actually affect the performance of a resonator. Most importantly, I demonstrate a method to prevent these changes. The second part of the presentation discusses the phase-noise performance of a resonator-based timing reference. The phase noise, especially the far-from-carrier phase noise, often scales inversely with the carrier power. Hence, researchers have developed various approaches to improve the power-handling capabilities of a resonator-based timing reference. However, these approaches have relatively limited applications since they often require special resonator designs, optimized operating conditions, or non-standard fabrication processes. In terms of general approaches, having a large input-driving amplitude Vac directly improves the power-handling performance. This is because Vac is proportional to the electrical-current amplitude I in an oscillator. Hence, the power-handling performance improves when Vac increases. However, this approach has not been utilized because of the preconception that instability occurs at large Vac, where nonlinearities arise and cause the indeterministic frequency-to-amplitude relation. In this part, I explain why this preconception is not applicable to closed-loop oscillators. More importantly, I experimentally demonstrate stable operation of a closed-loop oscillator beyond the limit dictated by the critical vibration amplitude. This means that one can improve the power-handling performance of MEMS oscillators by operating them in the nonlinear regime. -------------- next part -------------- An HTML attachment was scrubbed... URL: From mbaran at stanford.edu Fri May 13 09:26:48 2011 From: mbaran at stanford.edu (Maureen Baran) Date: Fri, 13 May 2011 09:26:48 -0700 Subject: Distinct Wallet Found Message-ID: <003c01cc118a$8ef6a6b0$ace3f410$@edu> Dear All, A concerned labmember and building dweller found a wallet last evening in or around the Allen building. If you have misplaced your wallet please come to my cubicle #41 and be prepared to describe your wallet. Thank you, Maureen Maureen Baran Stanford Nanofabrication Facility Lab Services Administrator mbaran at stanford.edu 650-725-3664 -------------- next part -------------- An HTML attachment was scrubbed... URL: From ashamloo at stanford.edu Fri May 13 13:25:32 2011 From: ashamloo at stanford.edu (Amir Shamloo) Date: Fri, 13 May 2011 13:25:32 -0700 Subject: PhD Oral Examination: Shankar Swaminathan (Thursday, May 27th, 9:30AM) Message-ID: <4DCD93BC.9020901@stanford.edu> li ----- Original Message ----- From: "Shankar Swaminathan" To: mse-students at lists.stanford.edu, mse-faculty at lists.stanford.edu, glamstuds at lists.stanford.edu, labmembers at snf.stanford.edu Sent: Friday, May 14, 2010 12:44:11 AM Subject: PhD Oral Examination: Shankar Swaminathan (Thursday, May 27th, 9:30AM) Nanoscale atomic-layer-deposited high- k gate oxides on Germanium: Interface engineering for highly-scaled MOS devices Shankar Swaminathan Department of Materials Science and Engineering Advisor: Dr. Paul C. McIntyre Location: Bldg. 200 Rm. 002 (History Corner 200-002) Date: Thursday, May 27, 2010 Time: 9:30 AM (refreshments served at 9:15 AM) Germanium (Ge) has emerged as a promising candidate for surface channels in highly-scaled field-effect-transistors (FETs), as performance and reliability issues are likely to limit the use of conventional Si-based complementary-metal-oxide-semiconductor transistors. Lack of a high quality and stable thermal oxide of germanium has prompted interest in the use of high- k (high dielectric-constant) gate dielectrics on Ge channels. An interface layer (IL) between the high- k film and the Ge substrate appears to be necessary to avoid large defect densities characteristic of atomically-abrupt high-k (ZrO 2 or HfO 2 )/Ge interfaces. Atomic layer deposition (ALD) is a useful high- k metal oxide film growth technique due to the precise nature of thickness control and uniformity of thickness for very thin films. The use of ALD to synthesize deposited ILs interposed between the Ge channel and an overlying high- k layer has not been studied extensively. In this context, we present three highlights from our work: First, we show that a pre-ALD surface functionalization by oxidant dosing improves the electrical characteristics of Pt/4nm ALD-Al 2 O 3 /p-Ge devices, as opposed to a conventional precursor-first ALD process. In situ x-ray photoelectron spectroscopy in the ALD ambient reveals the influence of hydroxyl (-OH) termination of the Ge surface in passivating dangling bonds that lead to fast trapping. The evolution of Ge-O bonding states during this pre-pulsing process is correlated with the observed improvements in hysteresis, frequency dispersion of the gate capacitance, and the passivation of fast (band-edge) and slow (midgap) interface states. Second, we present findings on the effects of scaling the physical thickness of the ALD-Al 2 O 3 (down to 1 nm) on important electrical parameters such as interface state density (D it ), capacitance density, fixed charge and leakage current density. The ultrathin-ALD-Al 2 O 3 / Ge interface shows no apparent interfacial suboxide (GeO x ) while retaining a low D it of 2x10 11 cm -2 eV -1 , indicating the potential of ALD-Al 2 O 3 as an interface passivation layer. Aggressive gate capacitance scaling necessitates the use of so-called ?higher-k? dielectrics such as TiO 2 (k > 25). However, the conduction band offset (CBO) of the TiO 2 /Ge interface is very low (~ 0.2eV), resulting in high gate leakage. We demonstrate that ultrathin (~ 1 nm) Al 2 O 3 ILs, owing to their large bandgap (~ 6.2 eV), enhance the CBO at the TiO 2 /Ge interface, and reduce the gate leakage by 4 to 6 orders of magnitude at flatband. The Pt-gated bilayer devices exhibit excellent C-V characteristics down to a capacitance-derived EOT of 1.2 nm. The permittivity of the amorphous/nanocrystalline ALD-TiO 2 films was in the range of 32-35. Forming gas annealing is beneficial in lowering the interface state density via formation of monolayer-thickness interfacial GeO 2 . Post-annealed devices exhibited a minimum D it ~ 3x10 11 cm -2 eV -1 near midgap. Finally, we show that thermally activated electron transport into shallow defect states in the TiO 2 (~0.25eV below the CB edge) near the TiO 2 /Al 2 O 3 interface appears to be responsible for a temperature-dependent dispersion of the accumulation capacitance density. The passivation of these defects is important to fully realize the potential of novel bilayer high- k gate stacks on germanium channels . -- Shankar Swaminathan Stanford Graduate Fellow '05 McIntyre Research Group 203P, McCullough (G-LAM) Stanford University, CA Ph: 650 796 6929 --++**==--++**==--++**==--++**==--++**==--++**==--++**== mse-students mailing list mse-students at lists.stanford.edu https://mailman.stanford.edu/mailman/listinfo/mse-students From amroy at stanford.edu Sat May 14 01:04:27 2011 From: amroy at stanford.edu (Arunanshu Roy) Date: Sat, 14 May 2011 01:04:27 -0700 Subject: Protecting wafer edges during a Si etch in TMAH Message-ID: Hi everyone, Can someone suggest a good way to protect wafer edges during a Si etch? My wafers are coming out with jagged edges and cannot undergo further processing. I am planning to apply ProTEK B3 using Headway to the edges of the wafer but I'm not sure if I will achieve good edge coating. Does anyone have useful tips for such a process? Thanks a lot, Arunanshu From heyi at stanford.edu Sat May 14 21:35:44 2011 From: heyi at stanford.edu (Linda He Yi) Date: Sat, 14 May 2011 21:35:44 -0700 Subject: Oven in CIS113 Message-ID: Dear all, Just wondering who used the oven in CIS 113 today? I put my samples in the oven and set it to 180 degree C yesterday at 5 pm for 24 hour annealing. And the oven is turned off when I came to the lab this afternoon. Can anyone who used the oven today tell me when the oven is turned off today or yesterday so that I can know the exact annealing time? Thanks, He Yi -------------- next part -------------- An HTML attachment was scrubbed... URL: From hyungkyu at stanford.edu Sun May 15 15:02:15 2011 From: hyungkyu at stanford.edu (hyungkyu lee) Date: Sun, 15 May 2011 15:02:15 -0700 Subject: ME PhD Oral Examination: Hyung Kyu Lee (Monday, May 16th, 2:00 pm) Message-ID: <17FE96BD-D209-4F62-9694-4633E05B42EE@stanford.edu> Stanford University Ph.D. Dissertation Defense Title: ?Frequency Stability of Micromechanical Resonators with Nonlinearities? Hyung Kyu Lee Department of Mechanical Engineering Advisor: Prof. Thomas W. Kenny Date: Monday, May 16th, 2011 Time: 2:00 pm (Refreshments at 1:45 pm) Location: Mechanical Engineering Research Lab (MERL, bldg. 660), Conference room (203) http://campus-map.stanford.edu/index.cfm?ID=02-660 Abstract: Frequency references are an essential component of electronics, and there is increased interest in miniaturized frequency references. This interest has heightened the need for MEMS resonator-based oscillators because they can provide frequency references at low cost in small packages. Of particular interest is the oscillators' the temperature stability and the phase noise performance: temperature stability must be low enough for the resonator to provide a stable reference signal, and the frequency references in RF devices must satisfy stringent phase noise specifications. The first part of the presentation discusses the effect of nonlinearities in a resonator on the temperature stability of the resonator-based timing reference. To achieve good temperature stability , various temperature compensation techniques have been developed. Some of these compensation techniques tend to demonstrate resonator performance by using open-loop network analyzer measurements. However, most applications require a closed-loop system, with the resonator embedded in a feedback loop to form an oscillator. Thus, temperature stability measured in a closed-loop is more accurate for real-world applications. If the temperature stability decreases when the resonator is part of a closed-loop, it is very undesirable. In this part, I explain how this undesirable change commonly occurs, and I demonstrate how they actually affect the performance of a resonator. Most importantly, I demonstrate a method to prevent these changes. The second part of the presentation discusses the phase-noise performance of a resonator-based timing reference. The phase noise, especially the far-from-carrier phase noise, often scales inversely with the carrier power. Hence, researchers have developed various approaches to improve the power-handling capabilities of a resonator-based timing reference. However, these approaches have relatively limited applications since they often require special resonator designs, optimized operating conditions, or non-standard fabrication processes. In terms of general approaches, having a large input-driving amplitude Vac directly improves the power-handling performance. This is because Vac is proportional to the electrical-current amplitude I in an oscillator. Hence, the power-handling performance improves when Vac increases. However, this approach has not been utilized because of the preconception that instability occurs at large Vac, where nonlinearities arise and cause the indeterministic frequency-to-amplitude relation. In this part, I explain why this preconception is not applicable to closed-loop oscillators. More importantly, I experimentally demonstrate stable operation of a closed-loop oscillator beyond the limit dictated by the critical vibration amplitude. This means that one can improve the power-handling performance of MEMS oscillators by operating them in the nonlinear regime. -------------- next part -------------- An HTML attachment was scrubbed... URL: From julesvan at stanford.edu Sun May 15 19:05:32 2011 From: julesvan at stanford.edu (Jules John VanDersarl) Date: Sun, 15 May 2011 19:05:32 -0700 (PDT) Subject: MSE PhD Oral Examination: Jules VanDersarl (Thursday, May 26th, 1:00 pm) In-Reply-To: <805657200.236788.1305510703647.JavaMail.root@zm02.stanford.edu> Message-ID: <529075411.236933.1305511532618.JavaMail.root@zm02.stanford.edu> University PhD Dissertation Defense "Interrogating, manipulating, and controlling nano-bio interfaces" Jules J. VanDersarl Department of Materials Science & Engineering Advisor: Prof. Nicholas A. Melosh Thursday, May 26th, 2011 1:00 pm (Refreshments at 12:45pm) Location: Paul G. Allen Auditorium (CIS-X 101) http://campus-map.stanford.edu/index.cfm?ID=04-055 Cells communicate through direct contact and soluble chemical signals. Mimicking an extracellular environment requires controlling these signals at micron length scales. Integrated circuits make electronic control at these scales trivial, but fluidic control at these length scales requires very different principles. Standard microfluidic devices can finely control flowing fluids, but fluid flow affects cells in a myriad of ways. Alternatively, diffusion based chemical delivery methods tend to be crude, ill defined systems that offer very limited control. Our lab has developed several techniques that combine the active spatial and temporal control of microfluidic systems with a delivery system that relies purely on diffusion. First, we show a silicon based array of nanoreservoirs underneath the cell culture surface which are used to store and release bioactive molecules. These reservoirs are opened and closed with electrochemical dissolution and deposition at a narrow reservoir opening. Next, we show an adaptation of traditional, elastomer based microfluidics. In these devices the cell culture area is separated from a microfluidic channel located directly underneath the chamber by a nanoporous membrane. The desirable microfluidic properties, including temporal and spatial control, are preserved, while fluidic flow over the cells is eliminated. Finally, we demonstrate a novel ?nanostraw? culture surface, which is combined with the previous device to offer fluidic access directly to the cell cytosol, creating a powerful tool with implications for cell delivery and sampling. -------------- next part -------------- An HTML attachment was scrubbed... URL: From amroy at stanford.edu Mon May 16 15:58:44 2011 From: amroy at stanford.edu (Arunanshu Roy) Date: Mon, 16 May 2011 15:58:44 -0700 Subject: PECVD oxide/ nitride for TMAH Si etch mask Message-ID: Hi labmembers, Has anyone tried masking the back (unpolished side) of a Si wafer with PECVD oxide or nitride during a Si wet etch in TMAH? I tried this once and did not get very good results with PECVD oxide. My guess at that time was that the roughness on the back of the wafer caused the SiO2 mask to come off. I switched to using double polished wafers then but I still have some samples with an unpolished back surface that I need to mask and pattern for the Si etch. The pieces already have metal on them so I cannot grow thermal oxide. Can anybody suggest a way to mask the unpolished back surface? Thanks a lot, Arunanshu From nharjee at stanford.edu Tue May 17 16:29:41 2011 From: nharjee at stanford.edu (Nahid Harjee) Date: Tue, 17 May 2011 16:29:41 -0700 Subject: EE PhD Oral Examination - Nahid Harjee, Monday, May 23, 2011; 8:00 a.m. Message-ID: Stanford University Oral Defense ? Department of Electrical Engineering Speaker: Nahid Harjee Advisor: Prof. Beth Pruitt Co-Advisor: Prof. David Goldhaber-Gordon Date: Monday, May 23, 2011 Time: 8:00 am (refreshments at 7:45 am) Location: McCullough 335 http://campus-map.stanford.edu/index.cfm?ID=04-490 Title Coaxial-Tip Piezoresistive Cantilever Probes for High-Resolution Scanning Gate Microscopy Abstract Scanning probe techniques provide a wealth of information about the nanoscale properties of materials and devices, ranging from surface topography to the presence of magnetic domains. In scanning gate microscopy (SGM), the current through a sample is recorded as a sharp, conductive tip that modifies the local electrostatic potential is scanned above the surface. SGM has been used to map current flow, carrier density and potential barriers. However, existing SGM probes produce broad electric fields that limit lateral resolution. In order to apply SGM effectively to nanostructures of recent interest including carbon nanotubes and quantum dots, there is a need for a probe that can produce highly-localized electric fields. This probe must also self-sense topography for tip-sample alignment, as conventional laser-based detection methods can disturb photosensitive samples. In this talk, I will present a new probe that integrates a coaxial tip, shielding electric fields up to the tip apex, and a piezoresistor to electrically measure cantilever deflection. First, I will discuss the optimization of probe geometry and operating conditions to maximize vertical displacement resolution and investigate the effect of tip shape on lateral resolution. Next, I will describe the development of a process to batch-fabricate the probes and compare two techniques to create sub-micron tip apertures with focused ion beam milling. Finally, I will provide images of the coaxial tip potential profile, obtained using a quantum point contact at cryogenic temperatures, which demonstrate that the coaxial tip can produce significantly narrower perturbations than standard, unshielded tips. -------------- next part -------------- An HTML attachment was scrubbed... URL: From eperalta at stanford.edu Tue May 17 17:02:27 2011 From: eperalta at stanford.edu (Edgar Peralta) Date: Tue, 17 May 2011 17:02:27 -0700 Subject: Lost clean beaker near computer next to EVBond tool Message-ID: Dear Labmembers, Last friday I forgot to put away a medium size (fits 4" wafer) beaker that was in a zipped plastic bag on the table next to the EVBond (across from SVGcoat). It had a couple of labels that read "EPERALTA", "DO NOT USE" on it. If you picked it up please let me know where I can find it, I'd like to not have to wait until tomorrow to buy a new one. Thanks, Edgar From shott at stanford.edu Thu May 19 07:47:55 2011 From: shott at stanford.edu (John Shott) Date: Thu, 19 May 2011 07:47:55 -0700 Subject: Fwd: IMPORTANT! Ginzton Demo Work, Weekend 05/21 & 05/22 Message-ID: <4DD52D9B.5040409@stanford.edu> SNF Lab Members: Following is the notice that there will be significant activity this weekend (5/21 and 5/22) at the Ginzton demolition site to break up much of the remaining foundation. This activity is currently scheduled from 6 a.m. until about 5 p.m. on both Saturday and Sunday. Folks using the Raith, AFM, and SEM inspection tools are most likely to be affected by this activity because of vibrations. Hopefully, this will conclude the worst of the vibrations during the demolition phase. Thanks, John -------- Original Message -------- Subject: IMPORTANT! Ginzton Demo Work, Weekend 05/21 & 05/22 Date: Thu, 19 May 2011 07:33:59 -0700 From: Kenny Green To: snflabmembers at stanford.edu, cis-building at cis.stanford.edu, ee-students at lists.stanford.edu, eefaculty at lists.stanford.edu, ee-adminlist at lists.stanford.edu, ee-academicstaff at lists.stanford.edu CC: Meyer, Sandy , Weeks, Merry , Radovic, Svjetlana The below notice is from the Project Manager, Svjetlana Radovic. Please do the needful. Kenny Hi All, In order to complete Ginzton " bunker conditions "(demo of building slab & foundations) we would like to work*_2 full days this weekend (Saturday 05/21 & Sunday 05/22)_* The *Contractor would start around 6 a.m. and finish at the late afternoon(around 5:00p.m. )_We would still carry on with the next week May of 23^rd morning work per initial schedule_.* This weekend work would be nice to have & would help wrapping up Demo project. Please let me know if you have any questions or concerns. It would be much appreciated if you can contact me ASAP Many thanks on your patience & work w/ us on this project. Regards, Svjetlana -------------- next part -------------- An HTML attachment was scrubbed... URL: From megrubbs at stanford.edu Thu May 19 09:25:55 2011 From: megrubbs at stanford.edu (Melody Ellen Grubbs) Date: Thu, 19 May 2011 09:25:55 -0700 (PDT) Subject: Melody E. Grubbs: PhD Defense - Tuesday, May 31st @ 2:30 PM in CISX-101 In-Reply-To: <1051127286.348119.1305761417398.JavaMail.root@zm02.stanford.edu> Message-ID: <358780340.364987.1305822355115.JavaMail.root@zm02.stanford.edu> T he Development of Amorphous Gate Metals for Threshold Voltage Variability Reduction in CMOS Devices Melody E. Grubbs Department of Materials Science and Engineering Advisors: Profs. Bruce M. Clemens and Yoshio Nishi When: Tuesday May 31st 2011 , 2:30 pm (Refreshments at 2:15 pm) Where: Paul G. Allen Auditorium (CIS-X 101) http://cis.stanford.edu/misc/directions.html Threshold voltage variability due to the polycrystalline nature of current metal gates has been identified as a problem in future generations of complementary metal oxide semiconductor (CMOS) devices. It has also been shown that the work function of these gates can vary by as much as 1 eV depending on the grain orientation. This means that as the gate dimensions become comparable to the metal grain size, the grain orientation distribution (and hence work function distribution) no longer averages out. This causes the threshold voltage to vary from device to device since the threshold voltage is directly related to the gate work function. In fact, work function differences as small as 0.2 eV have been shown to cause significant threshold voltage variation. In order to address this variability problem, we have developed amorphous, high temperature-stable, refractory transition metal-metalloid Ta-W-Si-B and Ta-W-Si-C metal gates. The amorphous microstructure of these materials has been shown to be stable at temperatures as high as 1100C. The work functions of these alloys have also been extracted and methods for tuning their work functions will be discussed. Additionally, since Ta-W-Si-C films have been shown to be amorphous and smooth, integrating these alloys into MOS devices may also reduce mobility degradation. Thus, Ta-W-Si-C has been integrated into long channel transistor devices in order to determine whether the effective channel mobility appears to be enhanced with respect to polycrystalline gates. Finally, we will discuss the experiments that have enabled Ta-W-Si-C to be easily integrated into deposition and processing as well as our ongoing collaboration with both Applied Materials and IMEC to integrate Ta-W-Si-C into short channel devices in order to confirm the reduction of threshold variability when compared to conventional polycrystalline metal gates. -------------- next part -------------- An HTML attachment was scrubbed... URL: From rschaevi at stanford.edu Thu May 19 15:34:35 2011 From: rschaevi at stanford.edu (Rebecca Schaevitz) Date: Thu, 19 May 2011 15:34:35 -0700 Subject: EE PhD Oral Examination - Rebecca Schaevitz, Thursday, June 2, 2011 at 3:00pm Message-ID: Stanford University Oral Defense ? Department of Electrical Engineering Speaker: Rebecca K. Schaevitz Advisor: Prof. David A. B. Miller Date: Thursday, June 2, 2011 Time: 3:00 pm (refreshments at 2:45 pm) Location: Allen-X Auditorium (formerly CIS-X Auditorium) - Room 101 Title A Simple Quantum Well Electroabsorption Calculator for the Germanium Material System Abstract Germanium is a unique material that is both CMOS-compatible and can be useful for optoelectronic devices. Leveraging existing CMOS technology, such as Reduced Pressure Chemical Vapor Deposition (RPCVD), Ge quantum wells are grown starting on pure Si substrates. The Ge wells exhibit strong electroabsorption behavior called the quantum-confined Stark effect (QCSE), which was unexpected in this material when it was first discovered at Stanford in 2005. With QCSE and Ge, we have the potential to develop highly CMOS-integrated optoelectronic modulators and bring optical interconnects to the short computer communication distances. However, given the novelty of the material system, we need the tools to design future devices that optimize performance. In order to create a tool that could allow for future material and device design, we developed SQWEAC, or the Simple Quantum Well Electroabsorption Calculator. SQWEAC effectively models the Ge/SiGe quantum well electroabsorption spectra using simple physical models. The use of simple models drastically speeds up the computation time compared to more common methods like k.p and tight-binding. In this presentation, I will describe SQWEAC and show its effectiveness in modeling current Ge quantum well material. I will also present future modulator device concepts that could meet the strict criteria of power, size, extinction ratio and insertion loss, and allow us to bring optical interconnects to the chip level. -------------- next part -------------- An HTML attachment was scrubbed... URL: From jihwanan at stanford.edu Sat May 21 16:20:42 2011 From: jihwanan at stanford.edu (JIHWAN AN) Date: Sat, 21 May 2011 16:20:42 -0700 Subject: Question about Al etch Message-ID: Hi all, I want to etch Al on YSZ(Y:ZrO2) substrate. Al is 30nm thick, depositied by sputtering. Does anybody have good recipe to etch Al ? also, does Al etchant etch Platinum too? I have some Pt on the substrate, and do not want it to be etched by Al etchant... Thank you all! Jihwan -- Jihwan An Ph.D. Candidate Nanoscale Prototyping Laboratory (NPL) Department of Mechanical Engineering Stanford University, CA cell : 650-862-0414 e-mail: jihwanan at stanford.edu -------------- next part -------------- An HTML attachment was scrubbed... URL: From nharjee at stanford.edu Sun May 22 10:44:35 2011 From: nharjee at stanford.edu (Nahid Harjee) Date: Sun, 22 May 2011 10:44:35 -0700 Subject: Reminder: EE PhD Oral Examination - Nahid Harjee; Monday, May 23, 2011; 8:00 a.m. Message-ID: Stanford University Oral Defense ? Department of Electrical Engineering Speaker: Nahid Harjee Advisor: Prof. Beth L. Pruitt Co-Advisor: Prof. David Goldhaber-Gordon Date: Monday, May 23, 2011 Time: 8:00 am (refreshments at 7:45 am) Location: McCullough 335 http://campus-map.stanford.edu/index.cfm?ID=04-490 Title Coaxial-Tip Piezoresistive Cantilever Probes for High-Resolution Scanning Gate Microscopy Abstract Scanning probe techniques provide a wealth of information about the nanoscale properties of materials and devices, ranging from surface topography to the presence of magnetic domains. In scanning gate microscopy (SGM), the current through a sample is recorded as a sharp, conductive tip that modifies the local electrostatic potential is scanned above the surface. SGM has been used to map current flow, carrier density and potential barriers. However, existing SGM probes produce broad electric fields that limit lateral resolution. In order to apply SGM effectively to nanostructures of recent interest including carbon nanotubes and quantum dots, there is a need for a probe that can produce highly-localized electric fields. This probe must also self-sense topography for tip-sample alignment, as conventional laser-based detection methods can disturb photosensitive samples. In this talk, I will present a new probe that integrates a coaxial tip, shielding electric fields up to the tip apex, and a piezoresistor to electrically measure cantilever deflection. First, I will discuss the optimization of probe geometry and operating conditions to maximize vertical displacement resolution and investigate the effect of tip shape on lateral resolution. Next, I will describe the development of a process to batch-fabricate the probes and compare two techniques to create sub-micron tip apertures with focused ion beam milling. Finally, I will provide images of the coaxial tip potential profile, obtained using a quantum point contact at cryogenic temperatures, which demonstrate that the coaxial tip can produce significantly narrower perturbations than standard, unshielded tips. -------------- next part -------------- An HTML attachment was scrubbed... URL: From alsune at stanford.edu Sun May 22 20:09:04 2011 From: alsune at stanford.edu (Wooshik Jung) Date: Sun, 22 May 2011 20:09:04 -0700 (PDT) Subject: [epi2] Reservation released from 23 May 2011 2:00pm~12:00am Message-ID: <1790269803.419880.1306120144825.JavaMail.root@zm03.stanford.edu> Sample will not be ready by then. Sorry for using this mailing but it seems I have some trouble of sending it the right mailing list. Thanks, Wooshik Jung From chongxie at stanford.edu Sun May 22 17:54:02 2011 From: chongxie at stanford.edu (Chong Xie) Date: Sun, 22 May 2011 17:54:02 -0700 Subject: PhD Oral Examination: Chong Xie (Tomorrow Mon May 23, 10am, CISX 101) Message-ID: Nanopillars for cellular interface *Chong Xie* Department of Materials Science and Engineering Research Advisor: Professor Yi Cui and Professor Bianxiao Cui * May 23rd (Monday), 2011 @ 10:00 am * (Refreshments served at 9:45 am) Location :* CISX Auditorium (101X)* http://cis.stanford.edu/misc/directions.html The small scale of nano-materials make them one of the best man-made candidates to interact with biological systems at subcellular or even molecular level. It has been the focal point of the research interests to interfacing live cells with one dimensional nanostructures, such as nanowires and nanopillars. In this presentation, I will first introduce the general behavior of cell growth and functions in the presence of nanopillars, and then cover two topics of my PhD research: using this unique structure to interface cells both electrically and optically. 1. We achieve improved electric interface between biological cells and solid state device by using arrays of vertically aligned nanopillar electrodes. Their tight attachment to the cell membrane allows us to acquire intracellular-like action potential signals non-destructively from cultured cardiomyocytes, which is responsible for various important cellular functions. 2. We demonstrate below-the-diffraction-limit observation volume *in vitro* and inside live cells by using vertically aligned silicon dioxide nanopillars. With a diameter much smaller than the wavelength of visible light, a transparent silicon dioxide nanopillar embedded in a nontransparent substrate restricts the propagation of light and affords evanescence wave excitation along its vertical surface. This effect creates highly-confined illumination volume that selectively excites fluorescence molecules in the vicinity of the nanopillar. We show that this nanopillar illumination can be used for *in vitro* single molecule detection with high fluorescence background. In addition, we demonstrate that vertical nanopillars interface tightly with live cells and function as highly localized light sources inside the cell. Furthermore, chemical modification of the nanopillar surface provides a unique way to locally recruit proteins of interest and simultaneously observe their behavior within the complex, crowded environment of the cell. -------------- next part -------------- An HTML attachment was scrubbed... URL: From benjamin.tee at stanford.edu Mon May 23 16:05:27 2011 From: benjamin.tee at stanford.edu (Benjamin Tee) Date: Mon, 23 May 2011 16:05:27 -0700 Subject: photodefinable HD8820 Message-ID: Dear labmembers, Does anyone have experience with HDmicrosystems photodefinable polyimide HD8820 in SNF? This seems like a good alternative to etching through the non-photodefinable PI2611 series. Thanks for any advice or suggestions! Ben -- Benjamin Tee Ph.D Candidate,?Electrical Engineering Stanford University Cell: 650-704-4300 M.S (EE) Stanford University '07 B.S.E (EE) University of Michigan - Ann Arbor '06 Bao Research Group -?http://baogroup.stanford.edu Address: 381 North South Mall Rm 209 Stanford CA 94305 USA From eperalta at stanford.edu Mon May 23 16:23:29 2011 From: eperalta at stanford.edu (Edgar Peralta) Date: Mon, 23 May 2011 16:23:29 -0700 Subject: Solder reflow? Message-ID: Does anyone know where I could do solder reflow on campus? Thanks, Edgar From shuhu at stanford.edu Tue May 24 08:53:16 2011 From: shuhu at stanford.edu (Shu Hu) Date: Tue, 24 May 2011 08:53:16 -0700 Subject: MSE PhD Oral Examination: Shu Hu (Monday, June 6th @ 10:00 AM in Clark Auditorium) Message-ID: <01e701cc1a2a$b1f31bf0$15d953d0$@edu> University PhD Dissertation Defense Nanoscale Germanium Crystal Growth and Epitaxy Control for Advanced Electronics and Solar Cells Shu Hu Department of Materials Science and Engineering Advisor: Prof. Paul C. McIntyre When: Monday, June 6th 2011, 10:00 am (Refreshments at 9:45 am) Where: James H. Clark Center Auditorium http://campus-map.stanford.edu/index.cfm?ID=07-340 Semiconductor crystal growth at the nanoscale and integration of different materials systems are central themes of materials research. They enable novel materials processes and device applications, and may shape the landscape of future technologies. A major challenge is growth of high-quality single crystal semiconductors (e.g. Ge) on large-mismatch (e.g. Si) and non-crystalline (e.g. glass) substrates, while managing the thermal constraints of the underlying substrates. As-grown vertical semiconductor nanowires have been demonstrated as sensors, and nanoelectronic and nanophotonic devices. However, little attention has been paid to their unique structural properties: vertical Ge nanowires can be epitaxially grown on (111)-oriented Ge and Si substrates. In my talk, I will focus on nanowire-seeded crystallization and metal-induced crystallization to realize three-dimensional integration and nanostructured solar cells. Fundamental aspects of crystal growth at the nanoscale will be discussed. Three-dimensional (3-D) device stacking and heterogeneous materials integration can improve the performance and functionality of Si-based electronics. First, I will demonstrate liquid phase epitaxy seeded by Ge nanowires to grow micron-sized single crystal Ge islands on SiO2. Vertical Ge nanowires can transfer the orientation and perfection of the underlying Si lattice to overlying layers several microns above. Liquid phase epitaxy was found to eliminate random nucleation that competes with epitaxial growth from nanowire seeds. The structure and electronic properties of Ge islands will be discussed. Given a low thermal budget annealing process, this technique can be repeated to build multiple active device layers, a key requirement for the fabrication of densely interconnected 3-D integrated circuits. Vertical, tapered Ge nanowire arrays have shown enhanced light absorption properties, promising for high-efficiency solar cells. Metal-induced crystallization is a low-temperature crystal growth process for polycrystalline semiconductor deposition on large-area, non-crystalline substrates. Then, I will demonstrate Al-induced layer exchange crystallization to form polycrystalline Ge thin films with micron-sized grains and (111)-preferred orientation at 200?C. The textured thin films can serve as growth templates for aligned nanowire arrays. Imaging nucleation, growth and coalescence of Ge crystal islands allows us to characterize, model and control Ge crystallization kinetics, by tuning the knobs such as nucleation density. -- Shu Hu, PhD Candidate Department of Materials Science and Engineering Stanford University 476 Lomita Mall, Stanford, CA 94305-4045 -------------- next part -------------- An HTML attachment was scrubbed... URL: From jwc at snf.stanford.edu Tue May 24 10:07:25 2011 From: jwc at snf.stanford.edu (James W. Conway) Date: Tue, 24 May 2011 10:07:25 -0700 Subject: Query of Interest from lab members working at SNF -- whom would be interested in using BeamPROP software application if we had it here at SNF? Message-ID: <4DDBE5CD.7090402@snf.stanford.edu> An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: moz-screenshot.png Type: image/png Size: 98636 bytes Desc: not available URL: From langrock at stanford.edu Tue May 24 10:18:07 2011 From: langrock at stanford.edu (Carsten Langrock) Date: Tue, 24 May 2011 10:18:07 -0700 Subject: Query of Interest from lab members working at SNF -- whom would be interested in using BeamPROP software application if we had it here at SNF? In-Reply-To: <4DDBE5CD.7090402@snf.stanford.edu> References: <4DDBE5CD.7090402@snf.stanford.edu> Message-ID: If the goal is to simply calculate the modes and effective indices of ridge waveguide structures, no matter how many layers, there are free alternatives available on the web. A Matlab-based mode solver was also written by somebody in Prof. James Harris' group. I am sure that BeamProp does a lot more things than this, but maybe not all of these might be required by the majority of users. Our group maintains solvers for diffused waveguides as well as semiconductor-based slab / ridge waveguides. Carsten On May 24, 2011, at 10:07 AM, James W. Conway wrote: > Greetings Lab Members and Ebeam Lab Users: > > A number of Users working in the Ebeam Lab are working with and > fabricating optical waveguides, splitters, and resonators as well as > other types of nano-optical Photonic devices. > This email is intended to solicit interest from our Users working in > the lab towards acquiring BeamProp software package for our Lab. > The intention would be to split the cost of this application between > SNF and another Stanford group for their users. The application > would be maintained on SNF computing equipment in the Ebeam Lab > and add to our tool set of CAD and modeling software as we move > into the future. > > Please lend me your opinion by replying to this email if you are > interested or have any comments... > > Thank you, > > James Conway > Ebeam Technology Group > Stanford Nanofabrication Facility > > > > Example of the software with many thanks from Stephanie Claussen: > > > > > > _____________________________________ Dipl.-Phys. Carsten Langrock, Ph.D. Physical Sciences Research Associate Edward L. Ginzton Laboratory, Rm. 202 Stanford University 348 Via Pueblo Mall 94305 Stanford, CA Tel. (650) 723-0464 Fax (650) 723-2666 Ginzton Lab Shipping Address: Astro-Physics Building, Rm. 148 452 Lomita Mall Ginzton Lab Freight Deliveries: 491 South Service Road _____________________________________ -------------- next part -------------- An HTML attachment was scrubbed... URL: From dinh at kaiamcorp.com Tue May 24 22:13:55 2011 From: dinh at kaiamcorp.com (Dinh Ton) Date: Tue, 24 May 2011 22:13:55 -0700 Subject: Lost keys Message-ID: Hi y'all, Did anyone find a set of key on Tuesday afternoon around 4:00-4:30pm? Please let me know. Thanks, Dinh Ton -------------- next part -------------- An HTML attachment was scrubbed... URL: From jprovine at stanford.edu Wed May 25 14:27:57 2011 From: jprovine at stanford.edu (J Provine) Date: Wed, 25 May 2011 14:27:57 -0700 Subject: burning/hot plate smell near chemical pass through (fiji area) Message-ID: dear labmembers, the heaters are baking out for the first time on the fiji. thus you will smell a burning/hot plate smell around the fiji (in the vicinity of the chemical pass through doors or wbgaas). this smell will dissipate overnight as the heaters bake out the absorbed moisture. please contact me if you have any concerns. j -------------- next part -------------- An HTML attachment was scrubbed... URL: From julesvan at stanford.edu Wed May 25 14:59:40 2011 From: julesvan at stanford.edu (Jules John VanDersarl) Date: Wed, 25 May 2011 14:59:40 -0700 (PDT) Subject: Reminder: MSE PhD Oral Examination: Jules VanDersarl (Thursday, May 26th, 1:00 pm) Message-ID: <1311707636.568597.1306360780466.JavaMail.root@zm02.stanford.edu> University PhD Dissertation Defense "Interrogating, manipulating, and controlling nano-bio interfaces" Jules J. VanDersarl Department of Materials Science & Engineering Advisor: Prof. Nicholas A. Melosh Thursday, May 26th, 2011 1:00 pm (Refreshments at 12:45pm) Location: Paul G. Allen Auditorium (CIS-X 101) http://campus-map.stanford.edu/index.cfm?ID=04-055 Cells communicate through direct contact and soluble chemical signals. Mimicking an extracellular environment requires controlling these signals at micron length scales. Integrated circuits make electronic control at these scales trivial, but fluidic control at these length scales requires very different principles. Standard microfluidic devices can finely control flowing fluids, but fluid flow affects cells in a myriad of ways. Alternatively, diffusion based chemical delivery methods tend to be crude, ill defined systems that offer very limited control. Our lab has developed several techniques that combine the active spatial and temporal control of microfluidic systems with a delivery system that relies purely on diffusion. First, we show a silicon based array of nanoreservoirs underneath the cell culture surface which are used to store and release bioactive molecules. These reservoirs are opened and closed with electrochemical dissolution and deposition at a narrow reservoir opening. Next, we show an adaptation of traditional, elastomer based microfluidics. In these devices the cell culture area is separated from a microfluidic channel located directly underneath the chamber by a nanoporous membrane. The desirable microfluidic properties, including temporal and spatial control, are preserved, while fluidic flow over the cells is eliminated. Finally, we demonstrate a novel ?nanostraw? culture surface, which is combined with the previous device to offer fluidic access directly to the cell cytosol, creating a powerful tool with implications for cell delivery and sampling. -------------- next part -------------- An HTML attachment was scrubbed... URL: From chenyw at stanford.edu Thu May 26 11:51:21 2011 From: chenyw at stanford.edu (Vincent Yi Wei Chen) Date: Thu, 26 May 2011 11:51:21 -0700 Subject: MSE PhD Oral Examination: Yi Wei Chen (Wednesday, June 8th @ 3:15 PM in Packard 101) Message-ID: <4DDEA129.40601@stanford.edu> University PhD Dissertation Defense *Atomic Layer Deposited Metal Oxides for Semiconductors Used in Aqueous Solutions* (Vincent) Yi Wei Chen Department of Materials Science and Engineering Advisor:Prof.Paul C. McIntyre When:*Wednesday, June 8th2011, 03:15 pm*(Refreshments at3:00pm) Where:*Packard 101* http://campus-map.stanford.edu/index.cfm?ID=04-030 In recent years, atomic layer deposition (ALD) has become a popular technique to deposit ultra-thin films with superior conformality and thickness control. Because of its unique surface adsorption-limited mechanism and the resulting capability of deposition at low temperatures and moderate pressures, ALD has found industrial applications in field effect transistor fabrication and coating of multilayer interconnection metallization.In this work, I have explored the potential of ALD-grown metal oxide layers in applications beyond typical electronics technologies. In particular, this research has focused on using ALD-grown metal oxides to enhance the performance and stability in aqueous solutions of biomolecular sensors and semiconducting anodes for photoelectrochemical fuel synthesis. In the biosensing application, we have replaced the SiO_2 gate dielectric material typically used in high sensitivity bio-field-effect-transistors (bioFET) with high dielectric constant HfO_2 . The SiO_2 bioFET gate dielectric suffers from poor stability and non-ideal dielectric response at the very small physical thicknesses required to achieve high sensitivity. ALD-grown HfO_2 , on the other hand, is capable of providing high capacitance density with a physically thicker dielectric layer, thanks to its large dielectric constant. With the ALD-HfO_2 gate dielectric, biosensor switching behavior was demonstrated using capacitance-voltage measurements in water, while at the same time maintaining the desired high capacitance. In addition, we have verified bio-functionalization of the HfO_2 film surface with biotin molecules via photoelectron spectroscopy, and detected streptavidin and avidin binding with capacitance-voltage analysis and molecular AFM imaging methods respectively. For the solar fuel synthesis, we have studied the behavior of ALD-TiO_2 tunnel oxides that can protect heretofore unstable semiconductors, such as Si, used as photoanodes in water splitting. For several decades, intense research effort has been devoted to identifying an efficient photoelectrochemical cell for oxidizing water under solar illumination.The resulting hydrogen and oxygen can be used to store energy from the intermittent terrestrial solar resource renewably, using water as a feedstock. However, photoanode materials choices have always been limited because the water oxidation half reaction at the anode surface is highly corrosive and requires large overpotentials. As a result, only oxidation-stable wide bandgap semiconductors such as TiO_2 and Fe_2 O_3 have been used as the photoanode.These photoanodes exhibit poor efficiency, however, because of their large bandgaps. Lower bandgap semiconductors, such as Si, are capable of absorbing solar light much more efficiently, but are easily corroded during water oxidation. In this work, a silicon photoanode was passivated by a thin and pinhole-free layer of ALD-TiO_2 such that efficient light absorption in the Si and the chemical stability of the TiO_2 can be exploited at the same time. This ALD-grown nanocomposite photoanode has been demonstrated to perform water oxidation with low overpotentials, while at the same time maintaining good stability with hours of continuous operation. The tunneling of electronic carriers through the thin ALD-TiO_2 , required to sustain high oxidation rates, has also been investigated by varying the TiO_2 thickness. -------------- next part -------------- An HTML attachment was scrubbed... URL: From yoneoka at stanford.edu Fri May 27 15:00:31 2011 From: yoneoka at stanford.edu (Shingo Yoneoka) Date: Fri, 27 May 2011 15:00:31 -0700 Subject: ME PhD Oral Examination - Shingo Yoneoka, Tuesday, May 31st, 1:00 pm Message-ID: University PhD Dissertation Defense *"ALD Metal Microbolometer Arrays"* Shingo Yoneoka Department of Mechanical Engineering Advisor: Prof. Thomas W. Kenny Co-advisor: Prof. Roger T. Howe Tuesday, May 31st, 2011 1:00 pm (Refreshments served at 12:45 pm) Location: Packard Building, Room 202 http://ee.stanford.edu/directions.php?bld=packard Abstract A bolometer is a device that measures the energy of incident electromagnetic radiation using electrical resistance change. One of the important applications of the bolometer is thermal imaging, which detects radiation in the long-wavelength infrared region (8-14 um). Conventional micromachined bolometers consist of multiple functional layers that optimize their performance. Vanadium oxide (VOx) and amorphous silicon are commonly used as thermistor. Silicon dioxide and silicon nitride are often used as the supporting and absorption layers because of their small thermal conductivity. These functional layers can be replaced by a single metal layer to further improve the thermal properties and simplify the fabrication process. However, this requires a film thickness on the order of nanometers since the impedance of the film must approach that of free space in order to absorb the wavelength of interest. In this talk, we present an uncooled infrared bolometer using a few-nanometer-thick platinum (Pt) film that is formed by atomic layer deposition (ALD). ALD is used to reliably deposit Pt films with less than 10-nm thickness. While Pt has relatively low TCR, it also has low 1/f noise, good linearity, and low hysteresis, making it a good temperature sensing material over all. Incorporating the U-shaped trenches, 50x50 um bolometer pixels and 25x25 um bolometer arrays made of ~12 nm ALD Pt/Al2O3 films are successfully fabricated. The aspect ratio of the freestanding structures fabricated in this process exceeds 4,000, which is much larger than the conventional MEMS devices. The developed process can provide unusual combination of electrical, thermal, and mechanical properties that will be useful for many applications. Having the fabrication technology for ALD-grown freestanding structures, the electrical and thermal conductivities of ALD Pt films of thickness 7.3, 9.8, and 12.1 nm are measured at 50-320K. Conductivity data for the 7.3-nm bridge are reduced by 77.8% (electrical) and 66.3% (thermal) compared to bulk values due to electron scattering at material and grain boundaries. The experimental Lorenz numbers of ALD Pt films exceed bulk values due to phonon conduction. Finally, the characterization results of the fabricated bolometer pixels and arrays are described. The thermal time constant of 50x50 um and 25x25 um bolometer pixels are 1.5 ms and 0.4 ms, respectively, which are about 10 times smaller than conventional VOx bolometers. The noise equivalent temperature difference of the bolometer is 112 mK assuming negligible 1/f noise. The presented bolometer is suitable for low-cost and high-speed thermal imaging applications. -------------- next part -------------- An HTML attachment was scrubbed... URL: From mtang at stanford.edu Fri May 27 23:16:27 2011 From: mtang at stanford.edu (Mary Tang) Date: Fri, 27 May 2011 23:16:27 -0700 Subject: Spring Term EE412 Final Presentations, Tuesday, May 31, 4:30 pm Message-ID: <4DE0933B.2080003@stanford.edu> Dear Labmembers -- Come and hear the final presentations of this term's EE412 projects. (And this term, there are projects for SNC!) *************************************************************** *EE412 Final Presentations:Tuesday, May 31, 2011* *4:30 pm in the AllenX Auditorium* *4:15-4:30 - Pizza (in or near the courtyard) * *4:30-4:50 -- "AGILE:Axially Graded Index Lens."Nina Vaidya.* Fabrication of thin film graded index lenses to concentrate light on solar cells. *4:50-5:10 --"Deposition of metal and dielectric films in the Intlvac sputtering system."Vijay Parameshwaran .* This project will describe the calibration and development of the Intlvac sputtering system for three materials: titanium, silicon dioxide, and tungsten.Additionally, the integration of these new tools within the SNF will be presented. *5:10-5:30 --**"Investigation of process for Metal Nitride films using ALD." Suhas Kumar and Adair Gerke.*** We investigate the process for deposition of metal nitride films (TiN, HfN) using the Savannah ALD system. We characterize the films to find the cause of many issues nitride films have had with the Savannah in the past. *5:30-5:50 -- "Mix-and-match: e-beam and optical lithography for optical waveguides and gratings."Chia-Ming Chang.* The fabrication of optical waveguides and gratings by using JEOL e-beam and ASML. *5:50-6:10 -- "Corrosion-Resistant ALD Coatings."Joey Doll and Alexandre Haemmerli* -------------- next part -------------- An HTML attachment was scrubbed... URL: From eperalta at stanford.edu Sun May 29 22:22:38 2011 From: eperalta at stanford.edu (Edgar Peralta) Date: Sun, 29 May 2011 22:22:38 -0700 Subject: Password for Computer to view microscope? (next to SVGdev) Message-ID: Hi All, Could somebody tell me the password for the computer next to SVGdev that is used to view the camera attached to the microscope? Thanks a lot, Edgar From arunanshuroy at gmail.com Mon May 30 13:58:49 2011 From: arunanshuroy at gmail.com (Arunanshu Roy) Date: Mon, 30 May 2011 13:58:49 -0700 Subject: Blue sticky tape as a mask during oxide etch Message-ID: Hello labmembers, I have previously used blue sticky tape as a mask for oxide etching at the WbGen. I now need to run a clean process and was wondering if the blue sticky tape is compatible with clean processing. Does anyone know if it is ok to use this tape in a clean process? Sincerely, Arunanshu From violetqu at stanford.edu Mon May 30 15:44:49 2011 From: violetqu at stanford.edu (Violet Qu) Date: Mon, 30 May 2011 15:44:49 -0700 Subject: ME PhD Oral Examination: Violet Qu (Tuesday, May 31, 10am, CISX-101) Message-ID: Stanford University Ph.D. Dissertation Defense *Title: ?Using a MEMS resonant strain gauge to study thin film stress relaxation?* Violet Qu Department of Mechanical Engineering Advisor: Prof. Thomas W. Kenny Date: Tuesday, May 31st, 2011 Time: 10:00 am (Refreshments at 9:45 am) Location: Paul G. Allen Building 101X auditorium (CISX-101) Abstract: Strain gauges have a wide range of applications. Besides measuring strain, they can be used to make other sensors such as load cells, pressure gauges, accelerometers, and gyroscopes. Of the various strain sensing techniques, a MEMS resonator based approach is particularly attractive because they offer superior sensitivity and resolution. Resonant strain gauges operate on the principle that the resonant frequency of a vibrating structure is a function of the applied strain. After reviewing some state of the art microresonator strain gauges, I will introduce our device -- a double ended tuning fork (DETF) resonator packaged at the wafer level using an epitaxial sealing technology (subsequently called the eSensor). These eSensors have sensitivities of up to 1500 ppm/microstrain, and dynamic strain resolution comparable to state-of-the-art devices (9 nanostrain with 10 kHz bandwidth). However, it is the mid- to long-term measurements where the eSensor really shines, thanks to the unparalleled long-term stability offered by the epi-seal. On the time scale of about a minute, the eSensor has a 0.4 nanostrain resolution. With its high sensitivity and resolution, the eSensor is a good candidate for thin film stress relaxation studies. In this part of the talk, I will show how stress changes in a thin film deposited on the outside of the eSensor can be measured. This approach is validated experimentally by using a sputtered platinum (Pt) film to generate a known thermal stress by performing a temperature sweep. The minimum stress change that can be resolved using the eSensor is 0.09 MPa for a 1 micron thick film. The last part of the presentation consists of preliminary results from probing the mechanical properties of ALD (atomic layer deposition) alumina films. ALD is a new and fast-growing field. The ALD technique promises to produce films of superior quality than the more conventional thin film deposition methods. Though ALD is finding more and more applications in research as well as manufacturing at lightening pace, characterization of the films' mechanical properties lags behind. The reason is, in part, because detecting stress signals from films only nanometers thick presents a real challenge to current technologies. Our experimental data show that the eSensor can clearly measure stress changes in ALD alumina films that are 65 to 80 nm thick. I will share interesting discoveries from these first experiments on the time evolution of stress in ALD alumina, and our attempts at understanding them. -------------- next part -------------- An HTML attachment was scrubbed... URL: From amroy at stanford.edu Mon May 30 14:59:45 2011 From: amroy at stanford.edu (Arunanshu Roy) Date: Mon, 30 May 2011 14:59:45 -0700 Subject: Experience with ProTEK PSB? Message-ID: Hi, Has anyone tried lithogrpahy with ProTEK PSB to make an etch mask for a long Silicon etch? I am thinking of using this process since I need to pattern the back (unpolished) surface of the wafer for Si etching and my process also requires me to make a low temperature etch mask. Thanks. Arunanshu From megrubbs at stanford.edu Tue May 31 00:02:47 2011 From: megrubbs at stanford.edu (Melody Ellen Grubbs) Date: Tue, 31 May 2011 00:02:47 -0700 (PDT) Subject: Melody E. Grubbs: PhD Defense - Today, May 31st @ 2:30 PM in CISX-101 In-Reply-To: <358780340.364987.1305822355115.JavaMail.root@zm02.stanford.edu> Message-ID: <1370656004.689930.1306825367155.JavaMail.root@zm02.stanford.edu> The Development of Amorphous Gate Metals for Threshold Voltage Variability Reduction in CMOS Devices Melody E. Grubbs Department of Materials Science and Engineering Advisors: Profs. Bruce M. Clemens and Yoshio Nishi When: Tuesday May 31st 2011 , 2:30 pm (Refreshments at 2:15 pm) Where: Paul G. Allen Auditorium (CIS-X 101) http://cis.stanford.edu/misc/directions.html Threshold voltage variability due to the polycrystalline nature of current metal gates has been identified as a problem in future generations of complementary metal oxide semiconductor (CMOS) devices. It has also been shown that the work function of these gates can vary by as much as 1 eV depending on the grain orientation. This means that as the gate dimensions become comparable to the metal grain size, the grain orientation distribution (and hence work function distribution) no longer averages out. This causes the threshold voltage to vary from device to device since the threshold voltage is directly related to the gate work function. In fact, work function differences as small as 0.2 eV have been shown to cause significant threshold voltage variation. In order to address this variability problem, we have developed amorphous, high temperature-stable, refractory transition metal-metalloid Ta-W-Si-B and Ta-W-Si-C metal gates. The amorphous microstructure of these materials has been shown to be stable at temperatures as high as 1100C. The work functions of these alloys have also been extracted and methods for tuning their work functions will be discussed. Additionally, since Ta-W-Si-C films have been shown to be amorphous and smooth, integrating these alloys into MOS devices may also reduce mobility degradation. Thus, Ta-W-Si-C has been integrated into long channel transistor devices in order to determine whether the effective channel mobility appears to be enhanced with respect to polycrystalline gates. Finally, we will discuss the experiments that have enabled Ta-W-Si-C to be easily integrated into deposition and processing as well as our ongoing collaboration with both Applied Materials and IMEC to integrate Ta-W-Si-C into short channel devices in order to confirm the reduction of threshold variability when compared to conventional polycrystalline metal gates. -------------- next part -------------- An HTML attachment was scrubbed... URL: From edmyers at stanford.edu Tue May 31 09:46:54 2011 From: edmyers at stanford.edu (Ed Myers) Date: Tue, 31 May 2011 09:46:54 -0700 Subject: Fwd: Spring Term EE412 Final Presentations, Tuesday, May 31, 4:30 pm Message-ID: <6.2.5.6.2.20110531094620.05a9b0c0@stanford.edu> >Date: Fri, 27 May 2011 23:16:27 -0700 >From: Mary Tang >To: labmembers at snf.stanford.edu >Subject: Spring Term EE412 Final Presentations, Tuesday, May 31, 4:30 pm > > >Dear Labmembers -- > >Come and hear the final presentations of this >term's EE412 projects. (And this term, there are >projects for >SNC!)*************************************************************** > > >EE412 Final Presentations: Tuesday, May 31, 2011 > >4:30 pm in the AllenX Auditorium > >4:15-4:30 - Pizza (in or near the courtyard) > >4:30-4:50 ? ?AGILE: Axially Graded Index Lens.? Nina Vaidya. > >Fabrication of thin film graded index lenses to >concentrate light on solar cells. > >4:50-5:10 ?"Deposition of metal and dielectric >films in the Intlvac sputtering system." Vijay Parameshwaran . > >This project will describe the calibration and >development of the Intlvac sputtering system for >three materials: titanium, silicon dioxide, and >tungsten. Additionally, the integration of >these new tools within the SNF will be presented. > >5:10-5:30 ? "Investigation of process for Metal >Nitride films using ALD." Suhas Kumar and Adair Gerke. > >We investigate the process for deposition of >metal nitride films (TiN, HfN) using the >Savannah ALD system. We characterize the films >to find the cause of many issues nitride films >have had with the Savannah in the past. > >5:30-5:50 ? ?Mix-and-match: e-beam and optical >lithography for optical waveguides and gratings.? Chia-Ming Chang. > >The fabrication of optical waveguides and >gratings by using JEOL e-beam and ASML. > >5:50-6:10 ? ?Corrosion-Resistant ALD >Coatings.? Joey Doll and Alexandre Haemmerli