[labnetwork] Black Layer Formation During Au E-Beam Evaporation

[Youry Borisenkov]

Hi,
You are probably using a Fabmate/graphite crucible. The black film you see
is carbon contamination.
It's mainly coming from the crucible but also from the chamber itself.
This definitely influences the deposition and the solution we found was:
1. using a Tungsten crucible. I can share more details about this and our
experience so far.
2. thoroughly cleaning the chamber

Thank you,
Youry

On Thu, Sep 17, 2026 at 7:43 AM Chandan H B <chandanachar95 at gmail.com>
wrote:

> Dear LabNetwork Community, We would like to seek inputs from cleanroom/fab
> facility managers and process owners regarding an issue observed during Au
> deposition in our E-Beam Evaporators. We have observed the formation of
> black/dark layer on
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> Dear LabNetwork Community,
>
> We would like to seek inputs from cleanroom/fab facility managers and
> process owners regarding an issue observed during *Au deposition in our
> E-Beam Evaporators*.
>
> We have observed the formation of *black/dark layer on the Au charge
> after a few melt cycles*. The observation occurs during repeated melting
> of Au in a tungsten liner/crucible. We are currently investigating whether
> this could be related to *material surface contamination, crucible/liner
> condition, outgassing, chamber history, or the Au pre-cleaning/conditioning
> procedure*.
>
> We would appreciate your experience on the following:
>
>    - Have you observed *black/dark spots or a black layer forming on Au
>    during repeated E-beam melting/evaporation*?
>    - What *Au purity and material form* do you use?
>    - Do you perform any *cleaning/degreasing of the Au charge before
>    loading*? If yes, what procedure?
>    - Do you follow a specific *crucible/liner cleaning or replacement
>    procedure*?
>    - If you have identified a *root cause or corrective action* for a
>    similar observation, any details would be highly appreciated.
>
> Our objective is to compare practices across facilities and determine
> whether this is a *material-handling, source/liner, chamber-condition, or
> process-related phenomenon*.
> Any suggestions/inputs are highly appreciated.
> Thanks in advance!
>
> Regards,
> CHANDAN H B
> THIN FILMS ENGINEER
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