Abstract: Based on the traditional oxidation process, 4H-SiC MOS capacitors were fabricated by wet re-oxidation annealing (wet-ROA). The oxide film quality was analyzed by I-V characteristics testing and the Flower-Nordheim (F-N) tunneling current model. The SiO₂/SiC interface trap density was calculated by the Terman method. The structures of SiO₂/SiC interfaces, which were obtained by different processes, were analyzed by XPS. The SiO₂/SiC interface fabricated by wet-ROA, with 10 MV·cm^-1 in the breakdown field strength of oxide film, 2.46 eV in the barrier height of SiO₂/SiC, 10¹¹ eV^-1·cm^-2 in the interface trap density, can meet the reliability requirement in fabricating devices.