Effect of irradiation with MeV protons and electrons on the conductivity compensation and photoluminescence of moderately doped p-4H-SiC (CVD)
The compensation of moderately doped p-4H-SiC samples grown by the chemical vapor deposition (CVD) method under irradiation with 0.9-MeV electrons and 15-MeV protons is studied. The experimentally measured carrier removal rates are 1.2–1.6 cm{sup –1} for electrons and 240–260 cm{sup –1} for protons. The dependence of the concentration of uncompensated acceptors and donors, measured in the study, demonstrates a linear decrease with increasing irradiation dose to the point of complete compensation. This run of the dependence shows that compensation of the samples is due to the transition of carriers to deep centers formed by primary radiation-induced defects. It is demonstrated that, in contrast to n-SiC (CVD), primary defects in the carbon sublattice of moderately doped p-SiC (CVD) only cannot account for the compensation process. In p-SiC, either primary defects in the silicon sublattice, or defects in both sublattices are responsible for conductivity compensation. Also, photoluminescence spectra are examined in relation to the irradiation dose.