Characteristics of He+-irradiated Ni Schottky diodes based on 4H-SiC epilayer grown by sublimation

Forward and reverse current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the of He+ – irradiated Ni-SiC(4H) Schottky diodes (SDs) are presented prior and after irradiation. The effect of irradiation was weakly observed in the region of small forward and reverse current, but series resistance of SD demonstrated tendency to rise with increasing irradiation dose. The most interesting effect was the big scatter of the series resistances after exposure to high irradiation dose 2×1012 cm-2. By contrast, uncompensated donor concentration had just minor changes (from 3.3×1017 cm-3 prior irradiation to 1.8×1017 cm-3 at highest irradiation dose) with no connection with SDs resistance. Hypothesis that localized defect-induced current paths could explain this behaviour is discussed. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)