09:30 〜 11:30
[16a-P5-10] 熱酸化膜/SiC界面近傍の不均一層とそのリーク電流特性
キーワード：SiC、界面、SiO2
The uniformity of SiO2 film thermally grown on 4H-SiC was characterized by atomic force microscopic observation of the emerged SiO2 surface after each step-etching using diluted HF solution. The two-dimensionally non-uniform film was inevitably formed in the vicinity of SiO2/SiC interface, where the step-etched SiO2 surface drastically becomes rough. The non-uniform film at the near-interface region was not uniformized by various post-oxidation-annealing. Meanwhile, it was found that uniformization of the near-interface region occurs at a distance from the interface. This means that the uniform region of the SiO2 film reproduces as the film thickness increases. In addition, electrical properties of MOS capacitors with SiO2 film with thicknesses of 5.1, 18.0, and 27.3 nm, which were thermally grown on 4H-SiC(0001), were characterized in a temperature range of 130~350 K. It was implied that the leakage current was dominated by Poole-Frenkel emission via the trap with the level of approximately 1.2 eV below the conduction band minimum in SiO2. In addition of the trap level, the slightly deeper trap level, 1.4 eV, was also observed in the 5.1-nm sample. Generation of these traps could be related to formation of the non-uniform region near the SiO2/SiC interface.