Vanadium donor and acceptor levels in semi-insulating 4H - And 6H-SiC

Academic Article

Abstract

  • The electronic levels of vanadium in semi-insulating 4H - and 6H-SiC have been reinvestigated using temperature dependent Hall effect and resistivity measurements at temperatures up to 1000 K in conjunction with electron paramagnetic resonance (EPR) and optical absorption measurements which were used to identify the charge state of vanadium in the material. Two distinct thermal activation energies were found for each polytype. The shallower of the two levels correlated with the presence of both V3+ and V4+ in the EPR and absorption experiments, demonstrating that this level is the vanadium acceptor level while the deeper level is the donor level for which the V4+ charge state was observed. The results for the V4+5+ donor level, EC -1.57±0.09 eV for 4H-SiC and EC -1.54±0.06 eV for 6H-SiC, are in agreement with the generally accepted values. However, the results for the V3+4+ acceptor level, EC -0.85±0.03 eV in 6H-SiC and EC -1.11±0.08 eV in 4H-SiC, are significantly higher than previously assumed. Variations in crystal quality and purity may explain the differences in the previously reported values for the donor and acceptor levels. © 2007 American Institute of Physics.
  • Authors

    Published In

    Digital Object Identifier (doi)

    Author List

  • Mitchel WC; Mitchell WD; Landis G; Smith HE; Lee W; Zvanut ME
  • Volume

  • 101
  • Issue

  • 1