[labnetwork] Gold e-beam deposition - carbon contamination

[Youry Borisenkov]

Hi All,
*I just wanted to thank everyone for their valuable inputs and provide a
short update on our tests.*

We switched to a Tungsten crucible. We were using a spacer in our previous
setup (with a Fabmate crucible), this allows lower deposition power since
it is important for some applications where the substrate needs to be kept
at low temperature.
To mimic this with the Tungsten crucible, I use a double crucible setup.*
7CC cup that holds the gold is placed inside the larger 15CC cup and then
into the pocket.* Both are Tungsten.
So far so good. No carbon contamination, and we will have to keep following
this over time.
I also make sure to keep the chamber as clean as possible and once we spot
contamination I expect to eliminate it using a simple wipe of the gold
surface with an ipa wipe.
I'm not 100% sure about the wipe down part, and I hope it will never have
to be tested :)

Thank you all again and happy Friday,
Youry


On Fri, Jan 31, 2025 at 11:59 AM Youry Borisenkov <yb2471 at columbia.edu>
wrote:

> Hi All and happy Friday,
> I know it is a topic that has been discussed multiple times, however, I'm
> still lacking a solution that works and will appreciate you sharing your
> experience.
>
> Currently we are using a Fabmate crucible, and getting some carbon
> contamination .
> For clean Gold layers we use thermal evaporation. The films are good but
> it requires a lot of gold.
>
> So far we tried using a Molybdenum crucible with and without a spacer. The
> issue with this approach was that eventually after some time, we get carbon
> contamination back. I believe it's present in the chamber and eventually a
> critical mass is built on top of the gold in the crucible, coming from the
> chamber.
>
> Were anyone successful in overcoming carbon contamination in their e-beam
> deposition overtime?
> What are the procedures you are following? Maybe cleaning more frequently?
>
> --
> Thank you,
> Youry Borisenkov
> CNI <https://cni.columbia.edu/columbia-university-clean-room>
> Columbia University
> CEPSR 1017, New York, NY, 10027, United States.
> <https://sustainable.columbia.edu/crown-commuter>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mtl.mit.edu/pipermail/labnetwork/attachments/20250221/002588aa/attachment.html>