ELECTRICAL INHOMOGENEITY IN ALLOYED AUGE-NI CONTACT FORMED ON GAAS

Electrical properties of alloyed AuGeNi contacts to p-type GaAs were investigated and analyzed as a means to investigate the nature of alloyed AuGeNi contacts to n-type GaAs. Experimental results on the p-type GaAs were analyzed with a parallel-contact model: the contact is composed of two kinds of areas with different properties. The barrier height of the alloyed junction obtained from the current-voltage relation was 0.64 eV, while that obtained from the capacitance-voltage relation was 1.1 eV. We explain the discrepancy by assuming that the contact area is composed of about 84% n+p junction with barrier height of 1.42 eV and about 16% Schottky junction with barrier height of 0.65 eV. We conclude that the AuGeNi contacts to n-GaAs also have the mixed structure, composed of about 84% of n+n contact and about 16% of the Schottky contact. © 1990.