Surface and interface analysis of GaSb/GaAs semiconductor materials

This paper presents a detailed study on the surface and interface of MOMS-grown GaSb on GaAs using XPS, AES and SIMS techniques. It is found by XPS that at the surface and near surface regions antimony exists in the forms of Sb ₂ O ₅ and GaSb, and correspondingly gallium exists in the forms of GaSb, Ga ₂ O ₃ and elemental Ga. AES analysis shows that the epilayer (GaSb) growth time has very limited influence on the width of interdiffusion region, and that the width of the interdiffusion region of GaSb/GaAs grown at different temperatures is 340 ± 30 Å, which is much smaller than that of InSb/GaAs grown by the same method. The reasons are believed to be related to the lattice mismatch and the dissociation energies for Ga-Sb and In-Sb bonds. More sensitive SIMS analysis reveals that there is a small amount of arsenic present at the GaSb epilayer, which increases with increasing temperature. Finally two different kinds of SIMS techniques are compared, one using Ar ⁺ as ion source and collecting only the ion of the element of interest, the other using Cs ⁺ as ion source and collecting the combination of the element of interest with the Cs ⁺ ion from primary beam. The latter is found to be more suitable for III-V semiconductor heterostructure analysis as a result of much improvement in overcoming the matrix effects.