[labnetwork] ebeam evap of Bismuth

[Youry Borisenkov]

Hi Kurt,
We “forced” the Bismuth users to try the “dirty” thermal evaporator for
their process first.
We make sure to deposit a 50-100 nm Ti film prior their deposition, a new
boat and a new Bi material is always used and the users pump overnight when
loading their samples, bringing the chamber pressure to high-8 mbar
pressure range. So far they (and we) are happy.
I got a negative feedback from the ebeam vendor with regards to
Bismuth deposition,
since it’s such a low melting/vapor pressure point metal. It will be very
hard to get rid of, because it will get on many unshielded surfaces.
Theoretically you can get over this issue by encapsulating the Bi with
thick Ti layer after Bi deposition in a shared ebeam tool, but luckily we
didn’t have to test this theory.

*So eventually we never tried it in the ebeam. *
I will be happy to hear from experience of someone who did, since we do get
many requests for Bi, and I’m not sure for how long we will be able to keep
accommodating these on the thermal evap.

Hope that is helpful.

Best,
Youry CNI- Columbia University

On Fri, Nov 11, 2022 at 3:42 PM Kurt Kupcho <kurt.kupcho at wisc.edu> wrote:

> Hi Labnetwork
>
>
>
> I am wondering if anyone out there allows the deposition of Bi in their
> ebeam evaporator and any potential problems it may cause related to safety
> or vacuum chamber contamination/particulate generation.
>
>
>
> Bismuth as a solid material seems rather safe but I have no experience
> with it in PVD tools.
>
>
>
> Any info or experiences you could share with me is much appreciated.
>
>
>
> Thanks
>
> Kurt
>
>
>
>
>
> Kurt Kupcho
>
> Materials Science Engineer
>
> Nanoscale Fabrication Center (NFC)
>
> University of Wisconsin
>
> 1550 Engineering Dr
> <https://www.google.com/maps/search/1550+Engineering+Dr?entry=gmail&source=g>
> .
>
> ECB 3110
>
> Madison, WI  53706
>
> E:  kurt.kupcho at wisc.edu
>
> T:  608-262-2982
>
>
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