There are a ton of recipes with H2SO4:H2O2: H2O
8:1:1
5:1:1
3:1:1
This family will barely etch the InP at all
It also works fine with InGaAsP

James

-----Original Message-----
From: weiquan yang [mailto:quanwy@gmail.com]
Sent: Tuesday, March 17, 2009 4:30 PM
To: mems-talk@memsnet.org
Subject: [mems-talk] selective etching InGaAs to InP

Hi, all. Do you know a wet InGaAs etchant with high selectivity to InP. I
etched InGaAs using InP as the mask. Because the InP is useful for our final
device, I looked for the solution with high selective etching InGaAs to
InP.The etching rate to InGaAs should be as big as possible, and the etching
rate to InP should be as small as possible. I tried HF+H2O2. the selectivity
is kind of OK, however it will react with SiO2, which is a useful layer in
our device. I  also tried  C6H8O7+H2O2. The etching rate to InGaAs is not
fast enough. Are there people who have experience in InGaAs and InP? Pls
give me some advice. Thanks a lot.