Defect Levels in High Purity Semi-Insulating 4H-SiC Studied by Alpha Particle Induced Charge Transient Spectroscopy

Abstract

Defect levels in high purity semi-insulating 4H silicon carbide substrates are studied by charge transient spectroscopy using 5.5 MeV alpha particles. A shallow defect level with the activation energy around 0.3 eV is found in all samples annealed at temperatures from 1400 to 1600 °C. Some other defect levels lying at deeper in the bandgap are found in samples annealed at 1400 and 1500 °C. As these deep levels are annealed out by 1600 °C, the series resistance of samples is decreased.