Nickel Schottky diodes were fabricated on 4H-SiC. The diodes had excellent current rectification with
about ten orders of magnitude between 50 V and +2 V. The ideality factor was obtained as 1.05 which
signifies the dominance of the thermionic emission process in charge transport across the barrier. Deep
level transient spectroscopy revealed the presence of four deep level defects in the 30–350 K temperature
range. The diodes were then irradiated with 5.4 MeV alpha particles up to fluence of 2.6 1010 cm 2.
Current–voltage and capacitance–voltage measurements revealed degraded diode characteristics after
irradiation. DLTS revealed the presence of three more energy levels with activation enthalpies of
0.42 eV, 0.62 eV and 0.76 eV below the conduction band. These levels were however only realized after
annealing the irradiated sample at 200 C and they annealed out at 400 C. The defect depth concentration
was determined for some of the observed defects.