Effect of defect bands on the electrical characteristics of irradiated GaAs and Si

Proton bombarded p-Si and neutron irradiated n-GaAs have been studied by DLTS, current-voltage, and capacitance-voltage measurements in metal-semiconductor junctions. The junctions were prepared by evaporation of Al onto silicon and of gold onto GaAs. Both junctions exhibited defect bands after bombardment. The bombardment has shifted the Fermi-level pinning position, increased the ideality factor in both junctions, and also affected the temperature dependence of the ideality factor and that of the capacitance. The results show that the main effect of the radiation is the generation of laterally inhomogeneous defects near the semiconductor surface.