Defects produced in 4H–SiC epitaxial layers by irradiation with a 200keV H+ ion beam to fluences ranging from 6.5 x 1011 to 1.8 x 1013/cm2 were investigated by using low-temperature (40K) photoluminescence. The defects produced by ion-beam irradiation introduced sharp so-called alphabet lines into the photoluminescence spectra in the 425 to 443nm range, due to recombination of excitons at defects. From the low-temperature photoluminescence lines intensity trend, as function of proton fluence, it was possible to single out two groups of peaks: the P1 lines (e, f, g) and the P2 lines (a, b, c, d) that exhibited different trends with the ion fluence. The P1 group normalized yield increased with ion fluence, reaches a maximum at 2.5 x 1012/cm2 and then decreases. The P2 group normalized yield, instead, exhibited a formation threshold at low fluence, then increased until a maximum value at a fluence of 3.5 x 1012/cm2 and decreased at higher fluence, reaching a value of 50% of the maximum yield. The behaviour of P1 and P2 lines, with ion fluence, indicated a production of point defects at low fluence, followed by a subsequent local rearrangement creating complex defects at high fluence.

Point Defects Induced in Ion Irradiated 4H–SiC Probed by Exciton Lines. G.Litrico, M.Zimbone, L.Calcagno, P.Musumeci, G.A.Baratta, G.Fotil: Nuclear Instruments and Methods in Physics Research B, 2009, 267[8-9], 1243-6