Hi guys,

I am starting to do RIE on III-V semiconductor superlattices.

However, most recent literature deals with high-selective etching
processes (GaAs <-> AlGaAs).

My aims are the following:

- etching depth around 1um
- high as well as no selectivity against AlAs
- high smoothness because I need to pos-process the sample.

We have in a parallel plate reactor the following gases available:
Cl2, BCl3, SF6, CHF3, CF4, He, N2 and O2.

Do you have any hints for recipes? I tried on a GaAs/InGaAs/AlAs/GaAs
structure 2sccm Cl2/8BCl3/12CHF3 (or He) but the results are not so
encouraging: Very rough etching borders as well as etching bottom
(Ra~30nm).

Greetings
Daniel