Fwd: Gallium Nitride

Mary Tang mtang at stanford.edu
Thu Apr 6 08:53:55 PDT 2006

Hi Jim --

But GaN is new to metalica, is that right?  And etching small amounts 
doesn't generally expose the user or the maintenance person to 
significant amounts of by-product, I would think.  The concern is that 
the ZnCdS incident in metalica left a discernable smell in the chamber 
and nearly caused (and probably warranted) an evacuation of the lab when 
the cryo was regened and one would think that the amounts and volatility 
of the potential by-products wouldn't have done this.  But the human 
nose can be extraordinarily sensitive.

I would vote for a conservative approach.  At the very least, the first 
couple of times that this is done, we should reserve extra time on the 
system to check everything out.


Jim McVittie wrote:

>GaN is not new to SNF. Our III-V users have been bring it into our lab for maybe 10 yrs.
>It has been etched in both Drytek4 and the PQ.   Jim
>Ed Myers wrote:
>>I was looking into the MSDS sheets for Gallium Nitirde.  There is not much
>>information on health hazards.  The only troubling item is the material is
>>water or humidity sensitive.  The released compound is ammonia.  I'm afraid
>>we might get an ammonia smell in the fab when we open the chamber and when
>>we regen the cryo.
>>Should we require a couple of partial vent-pumpdown cycles prior to lifting
>>the chamber?  The next question regards our internal hardware.  Can we let
>>them use ours or should we have them use the ZnCdS hardware?
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>>>From: "Jia Feng" <fengj at stanford.edu>
>>>To: <specmat at snf.stanford.edu>
>>>Cc: "FENGJ" <fengj at stanford.edu>
>>>Subject: Gallium Nitride
>>>Date: Wed, 22 Mar 2006 16:13:13 -0800
>>>X-Mailer: Microsoft Outlook Express 6.00.2800.1506
>>>Special Material Committee:
>>>I am writing to you to get your approval to use Gallium Nitride in SNF.
>>>The information you require is provided as follows.
>>>1. Your contact information: Name, Coral login, phone number, email
>>>address and who you work for (your PI or company.)
>>>Name: Jia Feng
>>>Coral login: fengj
>>>Phone number: 650-725-4549
>>>Email address: fengj at stanford.edu
>>>PI: James D Plummer
>>>2. The chemical or material.
>>>Material: Gallium Nitride
>>>Please see the MSDS in the attachment
>>>3. Vendor/manufacturer info: address and phone number, website URL.
>>>Technologies and Devices International, Inc.
>>>12214 Plum Orchard Dr., Silver Spring, MD 20904 USA
>>>TEL: +1 301 572 7834; FAX: +1 301 572 6435;   www.tdii.com
>>>4. Reason for request
>>>We are planning to do RF sputtering of Gallium Nitride onto 4-inch Silicon
>>>wafers and investigate its crystallization.
>>>5. Process Flow.
>>>(1) RF sputtering in metallica, thickness: ~ 0.1 um
>>>(2) Deposit 0.02-um SiO2 in sts PECVD
>>>(3) Optical lithography in nikon, using 3612 photoresist
>>>(4) Photoresist descum in drytek4
>>>(5) Dry etch in pquest
>>>(6) Photoresist removal in matrix
>>>(7) Clean in PRS-1000 (heated to 40 C) in wbgaas
>>>(8) Deposit 0.1-um SiO2 in sts PECVD
>>>(9) Heating to 800 C for 1 second in rtagaas
>>>(10) Cut the Silicon substrate using wafersaw. The GaN has already been
>>>etch into 1-um wide and 10-um long stripes and covered with SiO2. With
>>>visible marks etched on the wafer, the wafersaw blade will only cut into
>>>the Silicon substrate without contacting or exposing any GaN.
>>>6.. Amount and form.
>>>The Gallium Nitride we will bring into the lab is 1-inch poly-crystalline
>>>target for RF sputtering.
>>>7. Storage: Will you be storing your chemical/material at SNF? If so,
>>>please note any potential reactivities (this should be on the MSDS).
>>>We will store the Gallium Nitride target in vacuum sealed bags.
>>>8. DIsposal
>>>The Gallium Nitride will either be dry etched or stay on the wafer.
>>>Jia Fe
>>  ------------------------------------------------------------------------
>>                                                  Name: CCOHS MSDS Record Number 4173028.pdf
>>   CCOHS MSDS Record Number 4173028.pdf           Type: Acrobat (application/pdf)
>>                                              Encoding: base64
>>                                       Download Status: Not downloaded with message
>>                                                  Name: CCOHS MSDS Record Number 4168791.pdf
>>   CCOHS MSDS Record Number 4168791.pdf           Type: Acrobat (application/pdf)
>>                                              Encoding: base64
>>                                       Download Status: Not downloaded with message
>>   Part 1.4           Type: Plain Text (text/plain)
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Mary X. Tang, Ph.D.
Stanford Nanofabrication Facility
CIS Room 136, Mail Code 4070
Stanford, CA  94305
mtang at stanford.edu

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