Reactive ion etching of GaAs in CCl4/H2 and CCl4/O2

Abstract
The effect of CCl4/H2 on the etched shape and morphology of GaAs crystals compared with that of CCl4/O2 has been studied. Anisotropic etching with a residue‐free and smooth surface is obtained in CCl4/H2. Etching in CCl4/H2 shows an anisotropic shape for H2 ratios above 0.5 at 1.5 Pa. The etched surfaces are smooth for H2 ratios above 0.6, and Auger electron spectroscopy analysis shows that the surface is contaminated to a depth of 10 Å by CCl4. Raman spectra indicate that the surface is free from damage. CCl4/O2 etching rates show a maximum (1.7 μm/min) with an O2 ratio of 0.1 at 1.5 Pa, and etching profiles are isotropic The surfaces are seriously roughened in the case of O2 addition.