REGROWTH OF GAAS AT THE AU-GE-GA GAAS INTERFACE UNDER AN AS FLUX

Isothermal regrowth of doped GaAs at the Au/GaAs interface was studied using scanning electron microscopy and Auger electron spectroscopy. Electrical properties of the interface were characterized using I-V and C-V measurement. Multilayer films of AuGe(1500 angstrom) and Ga (200 angstrom) were evaported on chemically cleaned GaAs surfaces and annealed in N2 or an As flux. An n-type, moderately doped, nonuniform regrown GaAs layer was formed at the interface of the substrate with little reaction between the metal films and the substrate even after annealing at 450-degrees-C in an As flux. Current transport across the interface exhibited different behavior dependent upon whether regrowth had or had not regrown; (1) thermionic field emission (FET) through the grown GaAs/metal region, and (2) tunneling emission through the Au/original substrate interface area. Thicker Ga films results in nonuniform regrowth of GaAs both at the Au/air as well as the Au/GaAs interface.