CHANGES OF RIPPLE MORPHOLOGY OF CLEAVED Si SURFACE BY LOW-ENERGY Ar+ ION BEAM SPUTTERING

Abstract

We have investigated the changes of ripple morphology of an atomically flat cleaved Si surface due to Ar+ ion bombardment. The cleaved atomically flat and smooth plane of Si wafer was obtained by cutting vertically against the orientation flat of a Si (100) wafer. Then, the cleaved surface was bombarded by 1 keV Ar+ ion beam at ion incidence angle of 0°, 50°, 60°, 70°, and 80°. The ripples structure were depends on ion dose and angle formed on atomically flat surface at ion incidence angle of 50°, 60°, 70°, and 80°. Ripples were unclear and small at ion doses of 1.0 × 1018 ions/cm2 but pronounced at ion dose of 8.0 × 1018 ions/cm2. The wave lengths of ripples were measured and the maximum wave length is 425 nm at ion incidence angle of 70° and ion dose of 8.0 × 1018 ions/cm2. Results show that the wave length of ripple depends on ion doses and angle of ion incidence. It was also observed that the wave vector of ripple changes with changing the angle of ion incidence. This research is concluded by discussing the wave vector changing mechanism with the help of BH model.