Electrical characterization of high energy electron irradiated Ni/4H-SiC Schottky barrier diodes

Abstract

The effect of high energy electron (HEE) irradiation on Ni/4H-SiC Schottky barrier diodes was evaluated by current-voltage (I-V) and capacitance-voltage (C-V) measurements at room temperature. Electron irradiation was achieved by using a radioactive strontium source with peak emission energy of 2.3 MeV. Irradiation was performed in fluence steps of 4.9 × 1013 cm–2 until a total fluence of 5.4 × 1014 cm–2 was reached. The Schottky barrier height determined from (I-V) measurements was not significantly changed by irradiation while that obtained from (C-V) measurements increased with irradiation. The ideality factor was obtained before irradiation as 1.05 and this value did not significantly change as a result of irradiation. The series resistance increased from 47 Ω before irradiation to 74 Ω after a total electron fluence of 5.4 × 1014 cm–2. The net donor concentration decreased with increasing irradiation fluence from 4.6 × 1014 cm–3 to 3.0 × 1014 cm–3 from which the carrier removal rate was calculated to be 0.37 cm–1.