Doping of 6H-SiC pn structures by proton irradiation

The influence of proton irradiation on current-voltage characteristics, N-d -N-a values and parameters of deep centres in 6H-SiC pn structures grown by sublimation epitaxy has been studied. The irradiation was carried out with 8 MeV protons in the range of doses from 10(14) to 10(16) cm(-2). Irradiat ion with a dose of 3.6 x 10(14) cm(-2) leaves the voltage drop at high forw ard currents (10 A/cm(2)) practically unchanged. For higher irradiation dos e of 1.8 x 10(15) cm(-2), the forward voltage drop and the degree of compen sation in the samples increased; partial annealing of the radiation defects and partial recovery of the electrical parameters occurred after annealing at T similar to 400-800 K. Irradiation with a dose of 5.4 x 10(15) cm(-2) resulted in very high resistance in forward biased pn structures which rema ined high even after heating to 500 degrees C. It is suggested that proton irradiation causes decreasing of the lifetime and formation of an i- or an additional player. (C) 1999 Published by Elsevier Science B.V. All rights r eserved.