Fwd: Zn, Cd, S TXRF -> ZnCdS in Metallica

Michael Deal mdeal at stanford.edu
Mon Mar 28 17:20:51 PST 2005

First, the sulphur is 150E10, not 150E14.  Second, we usually have very 
high S on our wafers based on our TXRF measurements due, presumably, to the 
sulfuric/peroxide cleans as well as SO4 in cleanroom atmospheres - see the 
note at the end of Peter's report. (Also check out Rhett's TXRF's from last 
week, with 3000E10 S). Jim can confirm this.     -mike

At 04:52 PM 3/28/2005, Ed Myers wrote:
>I don't agree.  I feel we still need to control this process.  This is a 
>killer for our biological users and their gold substrates.  Sulphur 
>contamination of a gold surface inhibits almost all of the biological 
>surface attachment projects.  The TXRF data showed the sulphur to 
>be >150E14.  The other reason I feel we should control this process is the 
>way the system is used.  Typically each deposition is on a single 
>chip.  This greatly increases the number of required depositions and the 
>amount of sulphur in the system.
>If our goal is to keep all materials with vapor pressures less than In out 
>of the vacuum system, then we can not provide this project an open 
>door.  We should limit the number of depositions allowed per month.  We 
>should only need to support this process until the new sputter is available.
>Following the process down the line, these samples are also annealed in 
>RTAAG, a tool we have been telling users is semi-clean.  We should also 
>move their annealing process out of RTAAG, clean the system and get it 
>back to the advertised semiclean state.
>At 02:24 PM 3/28/2005, Michael Deal wrote:
>>Fellow specmat'ers,
>>     If we're not meeting tomorrow (due to people going to MRS), I think 
>> we can go ahead and approve this based on the numbers and his precautions.
>>                                                 -mike
>>>X-Sieve: CMU Sieve 2.2
>>>Date: Mon, 28 Mar 2005 14:17:46 -0800 (PST)
>>>From: Peter Griffin <griffin at stanford.edu>
>>>To: Michael Deal <mdeal at stanford.edu>
>>>Cc: specmat at snf.stanford.edu
>>>Subject: Zn, Cd, S TXRF -> ZnCdS in Metallica
>>>We have performed TXRF for a ZnCdS sputter deposition
>>>in the Metallica. Dedicated target holders, chimmney
>>>and wafer platten with custom designed inner and outer
>>>surrounding "bands" of 1 inch deep aluminium are used
>>>to minimize contamination. The dedicated equipment is
>>>removed after each deposition and can be bead-blasted
>>>clean at an outside facility as needed.
>>>Given that the TXRF levels are low-E11, this email is
>>>to request a review of the data and permission to run
>>>ZnCdS on a regular basis as needed.
>>>Thanks, Peter Griffin
>>>On Mon, 28 Mar 2005, Michael Deal wrote:
>>> > Peter,
>>> >        Did you send a request into specmat at snf.stanford.edu regarding 
>>> your
>>> > request?  We meet tomorrow at 1 pm (Tuesday) and we'll need a request in
>>> > order to approve it.  (If you have already sent in a request, can you 
>>> send
>>> > me a copy, since I haven't gotten it.)  Thanks.
>>> >                                               -mike
>>> >
>>> >

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