Ultra-low resistance NiGeAu and PdGeAu ohmic contacts on N-GaSb grown on GaAs

Ultra-low resistance ohmic contacts on n-GaSb with specific transfer resistances down to 0.12 Ω-mm and specific contact resistances of ~1.1e-6 Ω-cm² have been successfully fabricated on semi-insulating (SI) GaAs substrates using the Interfacial Misfit Dislocation (IMF) technique. The IMF technique enables epitaxial growth of GaSb layers on semi-insulating GaAs substrates resulting in vertical current confinement not possible on unintentionally ~ 1e17 cm^-3 p-doped bulk GaSb. Results for low resistance ohmic contacts using NiGeAu, PdGeAu, GeAuNi and GeAuPd metallizations for various temperatures are reported. The low annealing temperature of NiGeAu and PdGeAu metallizations show promising results, but the lifetime of a device with these contacts have not yet been studied.