Electrical and reliability characteristics of oxide grown by high pressure oxidation of SiC in nitric acid vapor with different gas ambients

High pressure oxidation of SiC in nitric acid vapor with two different gas ambients at two different temperatures has been studied. The oxide growth rate is greater than 20 nm/hr at 500°C. Leakage current density of 10nm thick oxide grown in nitrogen ambient at 500°C is much lower than that of the oxide grown in oxygen ambient with the same thickness. The field strength of the oxide grown in nitrogen ambient is also significantly higher (7.5 MV/cm) thanthat of oxide grown in oxygen (3.7 MV/cm). Not only the oxidation rate is higher in N2+HNO3 ambient, but the resulting oxide also shows excellent electrical and reliability characteristics at 500°C. In contrast to 500°C, the oxidation rate is lower in N2+HNO3 ambient than in O2+HNO3 ambient at 450°C. However, the leakage current density of 3.8 nm oxide grown in N2 ambient is two orders lesser than that of the oxide grown in O2 ambient of same thickness. The quality of oxide grown in nitrogen ambient is better than that grown in oxygen ambient at both temperatures.

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