[labnetwork] Question about ebeam evaporation of antimony triselenide (Sb2Se3)

[Timothy J Gilheart]

Hi Sandra,

I’d be concerned about both toxicity and vacuum system performance with this material, so I would decline such a request if I received it.

I have some direct experiences with both e-beam and thermal evaporation of Sb, but only in small amounts for a doping layer application. It sublimes and has relatively high vapor pressure, so it’s tricky to manage in either method. Toxicity concerns are much less with this element, but there is danger in acute or chronic exposure to inhaled powders. In my previous experience, I had just 2 nm of Ab sandwiched between a couple of other well-adhered metal films each almost 100 nm thick, so loose Sb flakes and powder was very unlikely for my applications, and our shield-cleaning vendor would accept parts with the level of Sb contamination we documented.

Se is both toxic and has high vapor pressure. I consider it a “no-go” material in all of our shared vacuum deposition tools, since we have little redundancy in our capabilities. If you had enough capacity to have a dedicated machine for Se and other materials of concern, maybe, but it’s still toxic.

With a higher melting point, I would expect Sb2Se3 to be better on the vapor pressure concern. but I don’t think the potential for toxicity goes away. In fact, when consulting the various thin film deposition guides freely available, the notes suggest co-evaporation of Se is needed to reduce stoichiometric variations, so that puts you right back into all the concerns surrounding Se.

Hope some of this perspective helps you make an informed decision for your context.

Best of luck with it,

-- 
Tim Gilheart, Ph.D.
Research Scientist - Nanofabrication Cleanroom Manager,
Shared Equipment Authority (SEA), Rice University
Cell: 832-341-5488 | Office: 713-348-3159 | gilheart at rice.edu

> On Jul 6, 2022, at 4:51 PM, Malhotra, Sandra Guy <sandra.malhotra at tamu.edu> wrote:
> 
> Howdy All,
> We have a user who would like to deposit antimony triselenide (Sb2Se3) in one of our ebeam evaporation tools. We are concerned about the toxicity of these materials, particularly where bead blasting of the kits is concerned. I'd like to ask the network if anyone has accommodated this material in their PVD tools, and if so, how they mitigated any toxicity concerns?
> 
> Thanks in advance for your inputs!
> 
> Best,
> 
> Sandra G. Malhotra, Ph.D.  |  Technical Lab Manager
> 
> AggieFab Nanofabrication Facility
> https://aggiefab.tamu.edu/ <https://urldefense.com/v3/__https://aggiefab.tamu.edu/__;!!BuQPrrmRaQ!nnNv75nE28AhhDe0AkUvwImi9BAcxzR82KSmrUL6I15XRGofbC6p97j-sKWucJmvciorcu5rfaWPBiZjhdnRHjlZh6InVybYAzAi5ko$>
> Department of Electrical & Computer Engineering, College of Engineering | Texas A&M University
> 3253 TAMU | College Station, TX 77843
> ph: 979.845.3199  |  sandra.malhotra at tamu.edu <mailto:sandra.malhotra at tamu.edu>
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