Hi Deepa, it may help us respond if you can give an indication of how much
mask undercut you can tolerate.  Many chemicals etch GaAs "fast" and the
degree of anisotropy can depend on the crystal planes.  Also, can you define
what is acceptably fast?

Regards,

Scott
----- Original Message -----
From: "deepa sree" 
To: 
Sent: Wednesday, August 23, 2006 2:04 PM
Subject: [mems-talk] Deep GaAs etching


> Hi
>
> I need to etch 3-4 mils of GaAs. I need to chemically etch it due to lack
> of facilities. Can anyone suggest a suitable masking layer and a fast
> chemical etchant that does this?