Deep-level defects in n-type 6H silicon carbide induced by He implantation

摘要

Defects in He-implanted n-type 6H-SiC samples have been studied with deep-level transient spectroscopy. A deep-level defect was identified by an intensity with a logarithmical dependence on the filling pulse width, which is characteristic of dislocation defects. Combined with information extracted from positron-annihilation spectroscopic measurements, this defect was associated with the defect vacancy bound to a dislocation. Defect levels at 0.38/0.44 eV (E_1/E_2), 0.50, 0.53, and 0.64/0.75 eV (Z_1/Z_2) were also induced by He implantation. Annealing studies on these samples were also performed and the results were compared with those obtained from e~--irradiated (0.3 and 1.7 MeV) and neutron-irradiated n-type 6H-SiC samples. The E_1 /E_2 and the Z_1/Z_2 signals found in the He-implanted sample are more thermally stable than those found in the electron-irradiated or the neutron-irradiated samples.