Dear members,
   I want to pattern Ni film on GaAs substrate by wet
etching. The one micron thick film was deposited by
E-beam. I used diluted HCl and H2SO4 and they did
work, but H2 bubbles generated during the etching
procedure made effect on the etching uniformity: they
all attached to the wafer surface. How to do with
these bubble? Or are there any other etchants which
can etch Ni but not GaAs, and don't release bubbles
during etching? Thanks!

ZHU X.P.