Effect of low-dose proton irradiation on the electrical characteristics of 4$H$-SiC junction diodes

The effect of low-dose proton irradiation (irradiation dose 10$^{10}$–1.8 $\times$ 10$^{11}$ cm$^{-2}$) on the capacitance–voltage, forward current–voltage, and reverse-recovery characteristics of 4$H$-SiC $p$–$n_o$ junction diodes is studied. Irradiation is performed with 1.8-MeV protons through a 10-$\mu$m-thick Ni-film (the proton energy and Ni-film thickness were chosen so that the projected proton range in silicon carbide is approximately equal to the $p$–$n_o$ junction depth). It is shown that proton irradiation in the above doses (i) does not change the concentration of majority carriers, (ii) leads to a dramatic decrease in the lifetime of nonequilibrium carriers (at a low injection level) (by several tens of times at the highest irradiation dose), and (iii) decreases the reverse-recovery charge at a high injection level (by up to a factor of 3 at the highest irradiation dose).