Abstract
Selective dry etching of GaAs to AlxGa1-xAs (x=0.3) using an etching gas composed of CCl2F2 and helium was studied. Etching was carried out at gas composition ratios of PCCl2F2 /PHe above 0.25, total pressures of 0.5 to 5.0 Pa, and power densities of 0.18 to 0.53 W/cm2. A high selectivity ratio exceeding 200 and a clean etch profile were obtained at a gas composition ratio of PCCl2F2 /PHe=1 operated at 5 Pa and 0.18 W/cm2. The etched profile of GaAs under the above conditions exhibited a nearly vertical-wall character.