Ohmic contact formation mechanism of the PdGeAu system on n-type GaSb grown by molecular beam epitaxy

Pd/Ge/Au/Pt/Au ohmic contacts on n-type GaSb grown by molecular beam epitaxy was developed to investigate the strong diffusion into the semiconductor for low temperature stress conditions. The resistivity was found to be very responsive to varying thickness of the different layers and to annealing conditions. Results of the microstructure analysis using sputtered neutral mass spectroscopy and cross-sectional transmission electron microscopy suggested that both the diffusion of Ge into GaSb and the formation of a PdGe state were essential to the annealing processes.