[labnetwork] Cadmium Telluride sputtering

[Bob Hamilton]

I suggest a review of the issue of tellurium breath, which can occur
at relatively low Te exposure rates:
http://en.wikipedia.org/wiki/Tellurium

You should use dedicated chamber hardware when sputtering CdTe. 

At the UC Berkeley Microlab we often invoke disposable shielding
(aluminum foil) to contain deposit residues and dispose of the such
shielding through our campus hazardous waste agents.

In addition, we fabricate dedicated chamber hardware such as the
target clamp rings, screws and substrate holders. These can then be
sent, as necessary to chemical cleaning companies who specializes in
semiconductor parts cleaning such as TMPI in Hayward, CA. 

Firms such as TMPI are trained and licensed to clean chamber hardware
and are qualified and used to working with toxic metals.

With proper caution and engineering solutions toxic metals can be
handled safely.
 
Bob Hamilton


Robert Hamilton
University of California at Berkeley
Microlab Facilities Manager
Rm406 Cory Hall
Berkeley, CA 94720-1770
510-642-2716
510-642-2916 (Fax)
510-325-7557 (Cell)
bob at silicon2.eecs.berkeley.edu


-----Original Message-----
From: labnetwork-bounces at mtl.mit.edu
[mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Bob Dutton
Sent: Sunday, June 21, 2009 2:08 PM
To: Keith Bradshaw
Cc: labnetwork at mtl.mit.edu; Duenes, Arnold; 'Roger Robbins'
Subject: Re: [labnetwork] Cadmium Telluride sputtering target exchange
problems

Keith Bradshaw wrote:
>
> We are getting a strong smell from the chamber and instant oxidation

> and flaking of product deposited on the chimney of our Sputtering 
> system when changing the Cad-Tel target.
>
> What is done to avoid this?
>
> Is this smell harmful?
>
> The flakes are very dark and seem to form when we open the system up

> to atmosphere. It is load locked so normally it doesn't see air.
>
> Keith Bradshaw
>
> 972-883-2099
>
> RL 10
>
> University of Texas at Dallas Clean Room
>
> NSERL building
>
>
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>   
Both Cadmium and Telurium are not good things!
Te can have a smell like garlic (probably one of the
trace elements in garlic anyway). Cadmium was
outlawed many years ago as a car-bumper coating,
again due to toxic properties...
I hope you folks have studied the safety books!
Bob Dutton
Stanford U.

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