Doping of 6H-SiC pn structures by proton irradiation

摘要

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. Irradiation with a dose of 3.6X10~14 cm~-2 leaves the voltage drop at high forward currents (10 A/cm~2) practically unchanged. For higher irradiation dose of 1.8X10~15 cm~-2, the frward voltage drop and the degree of compensation in the samples increased; partial annealing of the radiation defects and partial recovery of the electrical parameters occurred after annealing at T approx 400-800 K. Irradiation with a dose of 5.4X10~15 cm~-2 resulted in very high resistance in forward biased pn structures which remained high even after heating to 500 deg C. It is suggested that proton irradiation causes decreasign of the lifetime and formation of an i-or an additional p-layer. direct c 1999 Published by Elsevier Science B.V. All rights reserved.