Low-Temperature Dry Etching of GaAs and AlGaAs Using 92-MHz Anode-Coupled Chlorine Reactive Ion Etching

The etching characteristics and the damage induced by low-temperature etching have been studied using 92-MHz anode-coupled reactive ion etching. Due to the suppression of sidewall etching, vertical profiles of GaAs and AlGaAs have been obtained by lowering the substrate temperature during etching. The etching rates of GaAs and AlGaAs become identical at low temperatures. The exciton peak intensity in the photoluminescence spectrum decreased with a decrease in etching temperature, suggesting a slight increase in damage in low-temperature etching. It is also found that pronounced stoichiometry change in the subsurface region takes place in low-temperature etching.