High-pressure microwave plasma oxidation of 4H-SiC with low interface trap density

Microwave plasma oxidation under a relatively high pressure (6 kPa) region is developed to rapidly grow a high-quality SiO2 layer on 4H-SiC, based on a thermodynamic analysis of SiC oxidation. By optimizing the plasma power, an atomically flat interface is achieved, and the interface trap density is lower than that of standard 1300 °C thermal-oxidized and 1350 °C NO-annealed samples measured by various methods under multiple temperature conditions. Moreover, the oxide breakdown field is higher than 9.3 MV/cm, which is comparable to that of a sample produced by high-temperature thermal oxidation. Particularly, the results of electron energy loss spectroscopy show that the transition layer between 4H-SiC and SiO2 is lower than 2 nm, indicating that microwave plasma oxidation can greatly suppress the formation of interface defects. The results strongly demonstrate the effectiveness of high-pressure plasma oxidation for SiC.