Formation of Very Thin Anodic Oxide of InSb

An anodic oxide of InSb has been formed under a constant voltage to control thickness. It is found that the anodic oxide can be voltage-controlled up to 350 A with a very good optical flatness and up to 500 A if a small roughness is allowed. The surface roughness of the oxide increases drastically with increasing thickness. The transport number of oxygen ions in the oxide during anodization may be assumed to be 1 at least up to 750 A.