Thermal histories of defect centers as measured by low temperature photoluminescence in n- and p-type 4H SiC epilayers generated by irradiation with 170 keV or 1 MeV electrons

摘要

In this paper we describe an effort to find correlations between low temperature photoluminescence spectroscopy (LTPL) and deep level transient spectroscopy (DLTS) of electron irradiated samples annealed from 25 °C to 1700 °C in 100 °C steps. We report on thermal histories of defect centers created by 170 keV and 1 MeV electron irradiation, as observed by LTPL only. The DLTS results on "twin" samples are presented in a separate paper. Our results indicate that in n-type 4H SiC there is no correlation between the Z_1/Z_2 center in DLTS and the L_1 peak of the D_1 center seen in LTPL. In p-type 4H SiC we do not find a correlation between a 350 meV DLTS peak above the valence band and the LTPL L_1 peak of the D_1 center. Consequently, we cannot find evidence for a 350 meV ground state postulated in the "Pseudo-Donor" model [3].