Effect of Cluster Ion Bombardment on the Roughly Polished Surface of Single-Crystal Germanium Wafers

The surface treatment of single-crystal germanium with an argon cluster ion beam has been investigated. The initial surface of germanium wafers was bombarded by argon cluster ions with high (105 eV/atom) and low (10 eV/atom) specific energy. Using an atomic force microscope, images were obtained and the surface topography was compared before and after cluster ion bombardment. Using the power spectral density function of roughness, surface smoothing is demonstrated in the range of spatial frequencies: 1) ν = 1 − 8 µm−1 — for the high-energy mode; 2) ν = 0.7 − 2.5 µm−1 — for low-energy mode.