BCl[sub 3]/Ar ICP Etching of GaSb and Related Materials for Quaternary Antimonide Laser Diodes

Abstract

Inductively coupled plasma (ICP) etching of GaSb, AlGaAsSb, and InGaAsSb using BCl 3 /Ar plasma discharges was investigated for the fabrication of GalnAsSb/AlGaAsSb/GaSb laser diodes. Etching rates and selectivity were characterized as functions of gas flow ratio, accelerating voltage, and ICP source power, and the etching mechanism was discussed in detail. It is observed that the etch rate of GaSb and AlGaAsSb is much higher than that of InGaAsSb. The etched surfaces of GaSb, AlGaAsSb all have comparable root-mean-square roughness to the unetched samples over a wide range of plasma conditions; however, it is much rougher in etching of InGaAsSb. The selectivity between GaSb and AlGaAsSb was close to unity over the entire range of plasma conditions investigated, which is desirable for the fabrication of quaternary antimonide laser diodes. © 2005 The Electrochemical Society. All rights reserved.