Analysis of electronic levels in SiC: V, N, Al powders and crystals using thermally stimulated luminescence

The production of semi-insulating SiC depends on two issues: (i) the incorporation of a transition metal or further defects in the SiC lattice providing near midgap electronic levels; and (ii) the control of shallow and middle deep acceptors and donors. In this work a synthesis process for SiC powders doped with vanadium (V) as an amphoteric dopant is proposed. The incorporation of vanadium as electrically active VSi is monitored via photoluminescence (PL) measurements. Thermally stimulated luminescence (TSL) is used as a characterization technique for shallow levels in the crystals and powders. Recorded TSL glow curves are compared with numerical solutions of trap emptying processes revealing quantitative information on the activation energy of the ionization of shallow donors and acceptors. TSL emission and photoionization studies give information on existing deep levels.