Deep levels in electron irradiated semi-insulating 4H-SiC; Electronic, optical and structural observation

中根 浩貴*; 加藤 正史*; 市村 正也*; 大島 武; Ivanov, I. G.*; Trinh, X. T.*; Son, N. T.*; Janzn, E.*

no journal, , 

Deep level defects in Silicon Carbide (SiC) were studied using photo-induced current transient spectroscopy (PICTS), electron paramagnetic resonance (EPR) and photoluminescence (PL). Deep levels were introduced into high-purity semi insulating 4H-SiC samples by 2 MeV-electron irradiation. After the electron irradiation, the samples were annealed between 200 and 1000 C. In the samples annealed at 400 C or higher temperatures, we observed six different peaks from PICTS measurements. We labeled these peaks as a, b, c, d, e and f. As a result of the dependence of the peak heights on annealing temperature, the heights of all peaks increase monotonically with annealing temperature. In our previous report, we observed peaks labeled as A and B, which were speculated to be related to CV and the EI4 center identified by EPR. Peak temperatures and annealing behavior of peaks A and B are similar to those of peaks d and f, respectively, while other peaks a, b, c and e were not observed in our previous studies. The PL peaks at 433 and 442 nm were observed in all the studied samples, whereas peaks at 428 and 429 nm were observed in the samples annealed above 200 C, and a peak at 427 nm was observed in samples annealed above 400 C. Considering the annealing temperature dependence of the PICTS and PL peaks, the PL peak at 427 nm may correspond to either one of PICTS peaks a, b, d, e, and f.