In Situ Study of Low-Temperature Irradiation-Induced Defects in Silicon Carbide

Ni/4 H -SiC Schottky barrier diodes have been irradiated by 5.4-MeV helium ions at cryogenic temperatures and their electrical characteristics investigated. Only the prominent native defects ( E 0.11 , E 0.16 , and E 0.65 ) were observed before and after low-temperature irradiation at 50 K, with a baseline on the spectrum observed starting at 190 K. Low-temperature irradiation reduced the concentration of native E 0.11 and E 0.16 defects. After annealing at 380 K, E 0.37 , E 0.58 , E 0.62 , E 0.73 , and E 0.92 defects were observed. These results show that E 0.62 , an acceptor level of the Z 1 center, and E 0.73 , an acceptor level of the Z 2 center, are both secondary defects which are not formed directly from the irradiation process but from succeeding thermal reactions. An interpretation of the formation of the secondary defects is given.