SpecMat Logsheet, 4/10/06

Mary Tang mtang at stanford.edu
Mon Apr 17 17:00:24 PDT 2006

Hey Ed and other specmat'ers --

Jia Feng was just in my office asking about his GaN request.  It looks 
like he's ordered (with Peter Griffin) some 2" targets which they plan 
to use on the sputter tool in Nishi's lab, not metalica, after all.  
However, the other part of his request was for etching GaN in pquest and 
after a few other steps, including an RTA in rtagaas.

I've referred him back to you, because I'm not sure where the GaAs 
community stands on etching GaN (on silicon) in the pquest (is it 
considered part of the "GaAs process family" or the "silicon and 
everything else" family?)  I'm also not sure about heating GaN in an RTA 
(although Jia mentions that they plan to step up the temperature in 
stages, gradually -- besides, the GaN film is capped with sts pecvd film 
at this point, so this may not be a problem.)  His email of 3/22 
outlines his process request.

What do you all think?


Ed Myers wrote:

> SpecMat Members,
> This week is a light week for request.  Honoring one of our members 
> requests, there is not meeting this week.  I've outlined approaches 
> for each open item.  If I don't hear from you by week's end, I will 
> assume the proposals are accepted.
> 1) PVDF (Polyvinylidene fluoride) allowed in the clean equipment.
> The user is now looking at using ZnO (with options for PVDF and AlN).  
> Working with the user, he is still developing his process flow.  I 
> think we have a SemiClean / Gold process flow which works, except for 
> DRIE at the end of his processing.
> Recommendation:  If he is not etching the piezoelectric materials to 
> allow him in STSetch for his through wafer etch at the end of his 
> process.
> 2) GaN RF deposition in Metalica
> The concern arises from the tendency of this material to generate 
> ammonia gas when exposed to humidity.  I'm concerned we will pick up 
> odor complaints from metalica users.  Also the discoloration of the 
> internal hardware is what called attention to the deposition in the 
> first place.
> Recommendation:  Allow the deposition with the following restrictions.
> A) The RF circuitry needs to be inspected to insure the safety 
> modifications are functioning.
> B) Staff needs to be informed before each deposition
> C) Need to use the RF chamber hardware and not the general use hardware.
> 3) NR9G-1000PY Resist: The primary hazard is cyclohexanone
> Recommendation:  Approve with all the safeguards of cyclohexanone 
> resists the user is familiar with.
> 4) TaN using DRYTEK 2:
> Recommendation:  Approve
> 5) Spin-on Dopant (B-150) on the Headway
> Recommendation:  Depending on the MSDS approve for the headway and tylan4

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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