Defect Evolution in Ion Irradiated 6H-SiC Epitaxial Layers

Deep-Level Transient Spectroscopy and room temperature photoluminescence were used to characterise a 6H-SiC epitaxial layer irradiated with 10 MeV C+ and to follow the defect annealing in the temperature range 300-1400 °C. The intensity of luminescence peak at 423 nm, related to band to band transitions, decreases after irradiation and it is slowly recovered after annealing in the temperature range 1000-1400 °C. The DLTS spectra of low temperature annealed samples show the presence of several overlapping traps, which anneal and evolve at high temperatures. After 1200 °C a main level at Ec-0.43 eV (E1/E2) is detected. The comparison between luminescence and DLTS results indicates that the defect associated with the E1/E2 level is mainly responsible for the luminescence quenching after irradiation.