Highly selective etching of InGaAs on InAlAs in HBr plasma

A selective reactive ion etching (SRIE) process for the etching of InGaAs on InAlAs in HBr plasmas has been developed. A selectivity value as high as 160 was achieved at a bias voltage of -100 V. To date, this is the highest selectivity ever reported for this material system. The etch-stop mechanism is inferred from Auger electron spectroscopy to be due the formation of involatile aluminum oxide. The SRIE process reported should be for the fabrication of InAlAs/InGaAs/InP heterostructure field effect transistors (HFETs)