ABSTRACT
An etching selectivity- enhancing effect of fluorocarbon (CxFy) adsorption in GaAs/AlGaAs selective dry etching is reported. Then, a new selective etching technique using non-freon BCl3+CF4 plasma based on the selectivity enhancing mechanism is developed and demonstrated. The BCl3+CF4 plasma etching technique completely stops etch on an Al0.2Ga0.8As layer as thin as 15 Å, and therefore will be a successful solution to the undesirable threshold voltage variation of HJFET's.
