Deep level transient spectroscopic study of neutron-irradiated n-type 6H–SiC

Abstract

Deep level transient spectroscopy has been employed to study the deep level defects introduced in n-type 6H–SiC after neutron irradiation. Deep levels situated at EC−0.23, EC−0.36/0.44, EC−0.50, and EC−0.62/0.68 eV have been detected in the temperature range of 100–450 K, which have been identified with the previously reported deep levels ED1, E1/E2, Ei, and Z1/Z2, respectively. Thermal annealing studies of these deep levels reveal that ED1 and Ei anneal at a temperature below 350 °C, the Z1/Z2 levels anneal out at 900 °C, while the intensity of the E1/E2 peaks is increased with annealing temperature, reaching a maximum at about 500–750 °C, and finally annealing out at 1400 °C. The possible nature of the deep levels ED1, E1/E2, Ei, and Z1/Z2 are discussed in the context of their annealing behavior. Upon further annealing at 1600 °C, four deep levels labeled NE1 at EC−0.44 eV, NE2 EC−0.53 eV, NE3 EC−0.64 eV, and NE4 EC−0.68 eV are produced. Evidence is given that these levels are different in their origin to E1/E2 and Z1/Z2.