Reactive ion beam etching of InSb and InAs with ultrasmooth surfaces

The reactive ion beam etching (RIBE) of InSb and InAs using -Ar mixtures was investigated as a function of the gas mixture, ion beam energy, ion beam current density and etching time. It has been shown that with increasing :Ar ratio the morphology of the etched surfaces becomes very smooth. For an ion beam energy of 500 eV the surface roughness (root mean square) of InSb was reduced by more than 2 orders of magnitude because of the utilization of instead of Ar at moderate etching rates. Furthermore, in contrast to pure Ar sputtering, no increasing surface roughness with increasing etching time was observed for the RIBE process.