[labnetwork] Plasma etch of chalcogenides

[Tzu-Min Ou]

Dear Colleagues in the LabNetwork,

Good day! I got a request for the plasma etch of a chalcogenide that I have
zero experience with. So, I figure I should consult LabNetwork's
professional opinions before making any rush decision. Your response will
be extremely helpful to us.

We have a STS ICP etcher dedicated for Si DRIE. The chamber is carefully
kept clean that only photoresist and Si-based dielectrics are allowed
to present so far. Now, a faculty member wanted to etch a thin film of
GeSbSe in the chamber using CHF3 + Ar on a regular basis. I remember that
both Sb and Se are poisonous to the vacuum systems, but I cannot recall
exactly why. Here are my qestions:

1. Can anyone let me know how those elements are harmful to the vacuum
systems, please?

2. I tried to ask our EH&S people about the compatibility of the exhaust,
but they are not sure either. Is there a foreseeable compatibility issue in
the exhaust? Is it likely that we will need to have an inspection from the
authority, such as the fire department, etc., to be permitted to emit the
byproducts of this chalcogenide film?

3. Is it likely that the etch will cause any irreversible
contamination/change to the ICP system that cannot be recovered by
a standard cleaning process? (I was just worried that the Si DRIE will be
runined after this etch.)

Again, your opinion will be deeply appreciated. Thank you so much for your
time and help.

Sincerely,

Tzu-Min

-- 
Tzu-Min Ou, Ph.D.
Lab Manager
Colorado Nanofabrication Laboratory
Department of Electrical, Computer, and Energy Engineering
University of Colorado at Boulder
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