Enhanced selectivity in gaAs/GlGaAs selective Dry etching in BCl_3+CF_4 plasma by adsorbed CxFY for precise control of HJFET threshold voltages

摘要

An etching selectivity-enhancing effect of fluorocarbon (C_xF_y) adsorption in gaAs/AlgAsAs selective dry etching is reported. Then, a new selective etching technique using non-freon BCl_3+CF_4 plasma etching technique completely stops etch on an Al_(0.2)Ga_(0.8)As layer as thin as 15A and therefore will be a successful solution to the undesirable threshld voltage variation of HJFET's.