Point defects reactions in ion irradiated SiC

The defects produced in 4H-SiC epitaxial layers by irradiation with 800 key C(+) were characterized by Low Temperature Photoluminescence. Ion beam irradiation induces the formation of some sharp lines in the wavelength range 428-441 nm of the photoluminescence spectra, that are typically known as "alphabet lines". These photoluminescence features are due to the recombination of excitons at structural defects. The photoluminescence results allow to single out two groups of peaks: the P(1) lines (e-f-g) and the P(2) lines (a-b-c-d), that exhibit a different trend with the ion fluence. The P(1) group intensity increases with fluence and tends to reach a saturation value at high fluence. The P(2) group yield, instead, exhibits a threshold at low fluence and then increases toward a saturation. Subsequent UV-laser irradiation decreases the intensity of the P(2) lines related to a change in the structural configuration of the associated defects. (C) 2010 Elsevier B.V. All rights reserved.