Hi,

I need to remove about 60 nm thick of GaAs from a GaAs wafer.  I read
that GaAs can be wet etched in H2O2/H2SO4 solutions, but the etch rate
seems too high for me, couple of microns per minute.  Does anyone have a
recipe for slow etch so I can control the thickness removed?  I also
need smooth surface after etching.

Any help is appreciated.

Xinbing Liu