Non-annealed ohmic contacts to p-GaSb grown by molecular beam epitaxy

We fabricated Ti/Au, Pt/Au, Pd/Au, Ni/Au, and Au non-annealed ohmic contacts on p-type GaSb grown by molecular beam epitaxy. The specific contact resistivities were as low as 2.6×10−7 Ω cm2 for the as-deposited contact. Annealing was performed up to 250°C to see whether the heat treatment improves the contact. Thermal stability experiments were undertaken for the Pt/Au and the Au contact. Microstructure analysis of some metal–GaSb interfaces by cross-sectional transmission electron microscopy elucidates diffusion processes taking place at room temperature.