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

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 $E_C\text{−0.23,}$ $E_C\text{−0.36/0.44,}$ $E_C\text{−0.50,}$ and $E_C\text{−0.62/0.68\hspace{0.05em}}\mathrm{eV}$ have been detected in the temperature range of 100–450 K, which have been identified with the previously reported deep levels $\text{ED1,}$ $E_1{\mathrm{/E}}_2,$ $E_i,$ and $Z_1{\mathrm{/Z}}_2,$ respectively. Thermal annealing studies of these deep levels reveal that $\text{ED1}$ and $E_i$ anneal at a temperature below 350 °C, the $Z_1{\mathrm{/Z}}_2$ levels anneal out at 900 °C, while the intensity of the $E_1{\mathrm{/E}}_2$ 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 $\text{ED1,}$ $E_1{\mathrm{/E}}_2,$ $E_i,$ and $Z_1{\mathrm{/Z}}_2$ are discussed in the context of their annealing behavior. Upon further annealing at 1600 °C, four deep levels labeled $\text{NE1}$ at $E_C\text{−0.44\hspace{0.05em}}\mathrm{eV},$ ${\text{NE2\hspace{0.05em}E}}_C\text{−0.53\hspace{0.05em}}\mathrm{eV},$ ${\text{NE3\hspace{0.05em}E}}_C\text{−0.64\hspace{0.05em}}\mathrm{eV},$ and ${\text{NE4\hspace{0.05em}E}}_C\text{−0.68\hspace{0.05em}}\mathrm{eV}$ are produced. Evidence is given that these levels are different in their origin to $E_1{\mathrm{/E}}_2$ and $Z_1{\mathrm{/Z}}_2.$