OHMIC AND SCHOTTKY CONTACTS ON PHOTOCHEMICALLY PASSIVATED N-GAAS SURFACES

AuGe/Ni ohmic and titanium Schottky contacts were formed on n-GaAs surfaces which had undergone photochemical passivation prior to metal (ohmic and Schottky) deposition. Electrical measurements of ohmic and Schottky contacts indicate that photochemical passivation results in more stable and repeatable GaAs surfaces properties. Ohmic contacts on photochemically passivated surfaces reveal a greater degree of uniformity across the sample and from sample to sample even though there is no significant change in the mean specific contact resistance ρ{variant}c values compared with samples which were not passivated. Electrical characterization of Schottky contacts showed that photochemically passivated GaAs surfaces exhibited lower leakage currents and interface state densities than Schottky contacts formed on unpassivated GaAs surfaces. © 1991.