Capacitance Spectroscopy Study of Midgap Levels in n-Type SiC Polytypes

Abstract

As-grown and 116 keV electron-irradiated n-type 3C and 4H-SiC epilayers were electrically characterized by means of Fourier-transform deep level transient spectroscopy (FT-DLTS). A total of four deep levels, in the 0.20-0.73 eV range, below the conduction band, have been detected. By considering the band gap offset between 4H and 3C polytypes, we found that the deepest level in 3C-SiC labeled K3 (Ec-0.73 eV) has an energy position close to the EH6/7 level in 4H-SiC. An electron-dose dependence study of K3 and EH6/7, reveals that these two centers display a similar dose dependence behavior, suggesting that they may be related to the same defect.