Andrew,

Are you still using indium to mount your wafers in your MBE?  I stopped
using that method 10 years ago and found VEECO sells wafer holders and
custom holders for small pieces.
I would think spinning photo resist on your front side and a good bake
would provide plenty of front side protection if you still want to do a
wet etch.  Back when I did 1cm squares, I would use resist on the front
and a cotton swab with nitric acid for a quick clean up of the indium.
I didn't care about back side damage.

Brent

Andrew Irvine wrote:
> Hi all.
>
> Anyone out there have to etch indium from the back surface of their GaAs
> wafers after MBE growth?
>
> Any thoughts on how I can do it?
>
> Boiling conc HCl seems to do half a job (some kind of rough residual
> crud left over), and I can't find a suitable way of protecting the
> epitaxial surface.
>
> Yep, I'm asking the growers too!
>
> Many thanks,
>
> Andy
>
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