High quality Ohmic contacts having specific transfer resistances in the range 0.06≲ ρt≲0.2 Ω mm have been fabricated using Au/Ge/Ni/Ag based metallizations on AlGaAs/GaAs and AlInAs/GaInAs heterostructures. For AlGaAs/GaAs the metallization consisting of 100 Å Ni/800 Å 80 at. % Au–20 at. % Ge/1000 Å Ag/800 Å Au accomplishes this at alloy cycles with maximum sample temperatures 540≤Tmax≤600 °C. The corresponding results for Al0.48In0.52As/Ga0.47In0.53As were achieved with 100 Å Ni/450 Å Ge/800 Å Au/200 Å Ag/800 Å Au, and with alloy cycles having 430 °C≤Tmax≤490 °C. The two semiconductor systems have been studied electrically using the transmission line model and analytically with the help of sputter Auger depth analysis, optical and scanning electron microscopy, and energy dispersive x-ray analysis. In this paper we shall discuss the differences in temperature dependence of metallurgical interactions between the two systems and the corresponding electrical behavior.

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Low resistance ohmic contacts have been successfully fabricated on n-GaSb layers grown by MBE on semi-insulating (SI) GaAs substrates using the Interfacial Misfit Dislocation (IMF) technique. Although intended for photovoltaic applications, the results are applicable to many antimonide-based devices. The IMF technique enables the growth of epitaxial GaSb layers on semi-insulating GaAs substrates resulting in vertical current confinement not possible on unintentionally doped ~ 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. Specific transfer resistances down to 0.12 Ω-mm and specific contact resistances of < 2e-6 Ω-cm 2 have been observed.

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