High-Temperature Deep Level Transient Spectroscopy on As-Grown P-Type 4H–SiC Epilayers

Deep levels in as-grown p-type 4H–SiC have been investigated. Three hole traps, namely HK2, HK3, and HK4, were detected by deep level transient spectroscopy (DLTS) in the temperature range from 350 to 700 K. The concentration of each trap is approximately 1–3 ×10 12 cm -3 . Activation energy is estimated to be E V + 0.84 eV for HK2, E V + 1.27 eV for HK3, and E V + 1.44 eV for HK4. These hole traps may be donor-like (+/0) traps according to the double-correlated DLTS measurements. The concentrations of HK3 and HK4 decrease below the detection limit (1 ×10 11 cm -3 ) by annealing at 1350 °C. On the other hand, the HK2 center is thermally more stable, the annealing temperature being approximately 1550 °C.