[labnetwork] Bismuth evaporation

[Price, Aimee]

Hi everyone,
We have had a request to ebeam evaporate Bismuth.  We do not have any experience with this material but is a group V and has a relatively low melting point.  We have two evaporators and one we strictly limit the materials allowed within, including sources, substrates, and adhesives (none).  Our other one is a bit less restricted but we are still very careful about what we allow.  An example is that we do allow SiO2 deposition in the less restrictive evaporator. If approved, Bismuth would only be allowed in the less restrictive tool.  We are concerned about the low melting point and deposition on the chamber, potentially allowing for redeposition at a later date.

Does anyone have any experience with Bismuth evaporations?  Are there any considerations that you could share?  Our main concerns are safety and cross contamination, specifically mobile and deep level traps in compound semiconductors.

We do mostly compound semiconductor work but we do have some Si based devices/structures as well.  Below is from Lesker's website, which generally has terrific information on evaporation and sputter source materials.

(https://www.lesker.com/newweb/deposition_materials/depositionmaterials_evaporationmaterials_1.cfm?pgid=bi1
Melting point: 271C
10-8:  330C
10-6:  410C
10-4:  520C

Thanks in advance.

Best,
Aimee Bross Price

Manager, Nanofabrication
The Ohio State University
Nanotech West Lab
Institute for Materials Research
1381 Kinnear Road
Suite 100
Columbus, OH 43212
614-292-2753

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