特集「2020年日本表面真空学会学術講演会特集号Ⅰ」
SiO2/4H-SiCにおける界面準位と界面構造の相関
2021 年 64 巻 7 号 p. 312-317
詳細
2021 年 64 巻 7 号 p. 312-317
We have investigated the relationship between the electrical properties and the interfacial atomic structures of SiO2/4H-SiC interfaces, prepared by dry thermal oxidation procedures with 4H-SiC (0001) and 4H-SiC (000-1) substrates, using near-edge extended x-ray absorption fine structure (NEXAFS) spectroscopy and electrical methods. From capacitance-voltage measurements, SiO2/4H-SiC (000-1) interface exhibited 10 times higher interface state density than SiO2/4H-SiC (0001) interface. From NEXAFS measurements, we found that C and Si vacancies formed at the SiC side of SiO2/4H-SiC (0001) and SiO2/4H-SiC (000-1) interfaces, respectively. Compressive stress at the SiC sides of SiO2/4H-SiC (0001) and SiO2/4H-SiC (000-1) interfaces caused decreases in bond lengths. We concluded that a high density of interface states was related to a high interface stress and a high interface roughness.
