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

The Ni/4H-SiC Schottky barrier diodes (SBDs) and transfer lengthmethod (TLM) test patterns of Ni/4H-SiC Ohmic contacts werefabricated, and irradiated with 1~MeV electrons up to a dose of3.43$times 10^{14}$~e/cm$^{ - 2}$. After radiation, the forwardcurrents of the SBDs at 2~V decreased by about 50{%}, and thereverse currents at $-200$~V increased by less than 30{%}. Schottkybarrier height ($phi _{rm B} )$ of the Ni/4H-SiC SBD increasedfrom 1.20~eV to 1.21~eV under 0~V irradiation bias, and decreasedfrom 1.25~eV to 1.19~eV under $-30$~V irradiation bias. Thedegradation of $phi _{rm B} $ could be explained by the variationof interface states of Schottky contacts. The on-state resistance($R_{rm s}$) and the reverse current increased with the dose, whichcan be ascribed to the radiation defects in bulk material. Thespecific contact resistance ($rho _{rm c})$ of the Ni/SiC Ohmiccontact increased from 5.11$times 10^{ -5}~{Omega}cdot$,cm$^{2}$ to 2.97$times $10$^{ -4}~{Omega}cdot$,cm$^{2}$.