Behavior of a GaSb (100) Surface in the Presence of H₂O₂ in Wet-Etching Solutions

Gallium antimonide (GaSb) has an extremely high electron mobility and an excellent lattice match with various III-V ternary and quaternary compounds. In this study, the effect of wet-etching processes on the GaSb (001) surface was investigated, with a focus on the effect of H₂O₂. Dilution with H₂O and addition of H₂O₂ in HF/H₂O₂/H₂O, NH₄OH/H₂O₂/H₂O, and HCl/H₂O₂/H₂O mixtures produced different effects on the GaSb surface. The etching rate of GaSb increased with a high dilution ratio and a small amount of H₂O₂ in the mixture of NH₄OH/H₂O₂/H₂O. The addition of H₂O₂ in H₂O decreased GaSb oxide thickness and increased the contact angle on the GaSb surface and the XPS Ga 3d and Sb 3d_3/2 peak area ratios of Ga₂O₃/GaSb and Sb₂O₃/GaSb, which strongly imply that the H₂O₂ in the wet-etching solution served as an inhibitor of surface oxidation on GaSb. On the basis of the observed etching rates of GaSb, oxidation kinetics, contact angles, and chemical states, it is suggested that concurrent oxidation of GaSb and etching of oxidized GaSb occur on the GaSb surface in the presence of H₂O₂. Furthermore, the overall kinetics is determined by the relative amount of H₂O₂, which depends on the pH of the etching solution.