[labnetwork] [EXTERNAL] Gold e-beam deposition - carbon contamination

[Demis D. John]

Adding a tantalum pellet to the Au source will getter the carbon and reduce
spitting.

I can’t quite find the original paper, but here are some web pages that
reference it:
1)
https://compoundsemiconductor.net/article/116629/Tackling_the_foot#:~:text=concern.-,The%20combination%20of%20the%20crucible%20liner%20and%20tantalum%20%E2%80%98getters%E2%80%99%20looks%20like%20a%20win%2Dwin:%20the%20deposition%20rate%20increases%20while%20reducing%20gold%20spitting.,-But

2)
https://www.memsnet.org/memstalk/16896/#:~:text=look%20for%20a%20paperwritten%20in%20the%201970s%20that%20suggests%20adding%20a%20small%20piece%20of%20tantalum%20to%20yourgold.%20%20The%20Ta%20will%20not%20melt%20but%20it%20will%20control%20the%20spitting.


I don’t have measurements of carbon contamination with this - although we
do this in our e-beam evaporators.

-- Demis (contact info <https://wiki.nanotech.ucsb.edu/wiki/Demis_D._John>)
*Reminder*: The NanoFab has a publications policy
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On Sat, Feb 1, 2025 at 05:17 Czwakiel, James <czwakj at rpi.edu> wrote:

> Youry
>
> Once contamination is detected…. Clean clean clean
> All metal covers removed and blasted and ultra sonically cleaned
> Plus …. Make sure crucibles are not touched even with gloved hands…..
> always use tweezers
>
> James Czwakiel
>
> Semiconductor Equipment Engineer
>
> [image: Image]
>
>
>
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> ------------------------------
> *From:* labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of Youry
> Borisenkov <yb2471 at columbia.edu>
> *Sent:* Friday, January 31, 2025 11:59:09 AM
> *To:* Fab Network <labnetwork at mtl.mit.edu>
> *Subject:* [EXTERNAL][labnetwork] Gold e-beam deposition - carbon
> contamination
>
>
> *CAUTION:* This email originated from outside of the organization. Do not
> click links or open attachments unless you recognize the sender and know
> the content is safe.
> 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>
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