Evaluation of interface atomic structures and valence band off-set for SiO/4H-SiC formed by thermal oxidation

Watanabe, Heiji*; Kirino, Takashi*; Kagei, Yusuke*; Harries, J.; Yoshigoe, Akitaka ; Teraoka, Yuden; Mitani, Shuhei*; Nakano, Yuki*; Nakamura, Takashi*; Hosoi, Takuji*; Shimura, Takayoshi*

Channel registibity of SiC-MOSFETs becomes larger with decreasing carrier mobility due to defects in the SiO/SiC interface. Although channel mobility is larger than that of 4H-SiC(0001)Si face in the MOSFET fabricated on the 4H-SiC(000-1)C face, degradation of reliability for an oxide layer is remarkable. Valence band off-set and interface level density of the SiO/SiC interface are different from the former 4H-SiC(0001)Si face. Physical origins for these characters has not known yet. Thus, in order to make clear the origin of reliability degradation and interface characteristics of (000-1)C face, the energy band structure and chemical bonding states of the SiO/SiC interface formed by thermal oxidation.