RELATIONSHIP BETWEEN DEFECT LUMINESCENCE IN 6H-SIC AND DEEP-LEVEL CENTERS

Luminescence spectra and parameters of deep-level centers of p-n struc tures fabricated on the basis of 6H-SiC by different fabrication metho ds have been investigated. It was found that if there are deep-level a cceptors of the i-center type (E(upsilon)+0.52 eV) in such structures, the electroluminescence maximum of the p-n structures is in the green region of the spectrum (hnu almost-equal-to 2.35 eV). The dependence of the electroluminescence intensity on the forward current density J and temperature was investigated. It was shown that an increase in J s hifts the electroluminescence maximum toward the short-wavelength regi on (approximately 30 nm), and that the electroluminescence relaxation is nonexponential in nature. Comparison of different models for the ra diative recombination has shown that the donor-acceptor recombination model, in which the acceptor level is attributed to the i center and t he donor level to nitrogen, gives the best fit to experimental data.