Vacancy-related defects in ion-beam and electron irradiated 6H–SiC

A brief review is given on EPR study of irradiation-induced defects in SiC. The results of low-temperature study of Ky1 and Ky2 centers reveal for both of them the CS symmetry, spin S=12 and close coincidence of the g-tensor components. For Ky2 defect the principal values of g-tensor have been determined as gz=2.0048, gx=2.0022 and gy=2.0037, where z and x directions reside in the (1 1 2̄ 0) plane and the z-axis makes up an angle 65° with the c-axis. The same residence of z- and x-axis and an angle 59° are found for Ky1 center, gz=2.0058, gx=2.0025 and gy=2.0023. A comparison of experimental and calculated hyperfine (HF) parameters is presented which suggests that Ky2 and Ky1 defects can be assigned to the positively charged carbon vacancy in 6H–SiC. The EPR study of defects created along the Al+ ion track in n-type 6H–SiC shows that lineshape, linewidth and integral intensity of the EPR signal reflect the state of damaged layer generated by ion implantation. A variation of defect density with annealing is reported and defect origin is discussed.