Low-damage anisotropic radical-beam ion-beam etching and selective chemical etching of focused-ion-beam-damaged GaAs substrates

摘要

Abstract: We demonstrate the flexibility of radical-beam ion-beam etching for anisotropic low-damage dry etching and in situ processing of GaAs/AlGaAs structures. High anisotropy and low damage are verified by the light-current characteristics of etched laser facets and from Schottky diode characteristics of etched surfaces. These data show that damage is reduced by increasing the ratio of chemical to physical etching components. We also demonstrate direct-write patterning by selective chlorine etching of focused ion beam-damaged GaAs. The depths and linewidths are measured by atomic force microscopy. The enhanced etching is correlated to the implant-damage distribution. A selectivity of 10 to 1 is attained for doses equal or above 5 $MUL 10$+14$/ cm$+$MIN@2$/, which corresponds to the amorphization threshold in GaAs.!30