High energy electron radiation effect on Ni/4H-SiC SBD and Ohmic contact

The Ni/4H-SiC Schottky barrier diodes (SBDs) and transfer length method (TLM) test patterns of Ni/4H-SiC Ohmic contacts were fabricated,and irradiated with 1 MeV electrons up to a dose of 3.43×10 14 e/cm 2.After radiation,the forward currents of the SBDs at 2 V decreased by about 50%,and the reverse currents at 200 V increased by less than 30%.Schottky barrier height (φ B) of the Ni/4H-SiC SBD increased from 1.20 eV to 1.21 eV under 0 V irradiation bias,and decreased from 1.25 eV to 1.19 eV under 30 V irradiation bias.The degradation of φ B could be explained by the variation of interface states of Schottky contacts.The on-state resistance (R s) and the reverse current increased with the dose,which can be ascribed to the radiation defects in bulk material.The specific contact resistance (ρ c) of the Ni/SiC Ohmic contact increased from 5.11×10 5 · cm 2 to 2.97×10 4 · cm 2.