Fundamental Aspects of Silicon Carbide Oxidation

Silicon carbide (SiC), which exhibits a wider band gap as well as a superior breakdown field and thermal conductivity over conventional Si, has gained considerable attention for future power electronics [1]. Among the various types of power devices, metal-oxide-semiconduc‐ tor field-effect transistors (MOSFETs), which provide a normally-off characteristic, should become a key component for next-generation green electronics. As stated, with the excep‐ tion of Si, SiC is the only compound semiconductor that yields SiO2 insulators with thermal oxidation. This makes the device fabrication process easier compared with those for other wide band gap semiconductors. It is commonly believed that carbon impurities within the oxides diffuse out in the form of carbon oxides during high temperature oxidation, but a small amount of carbon impurities remains within the oxide and at the SiO2/SiC interface. Consequently, the electrical degradation of SiC-MOS devices causing both deteriorated de‐ vice performance and reliability is the most crucial obstacle to the implementation of SiCbased power electronics.