Hi Margolle
SiCl4, CF4, O2 and He are used also for high slective
etching of AlGaAs/GaAs with different ratios it can be
achieved ansiotropic as well isotropic etch for low Al mole
fraction, I donot know what Al mole fraction you are
using..
it is good to have look at the reference - J of Electrochem
Soc. Vol 140, No7 July 1993 pp 2116.
Good luck !!!!!
Kumar Parshant
MML Maryland
Yahoo! - Official partner of 2002 FIFA World Cup
http://fifaworldcup.yahoo.com