Abstract: This article reports on the study of the transition region of a SiO2/4H-SiC interface prepared by dry oxidation using ADXPS.The study contains interface composition,component distribution and so on.We prepared the samples with oxidation thicknesses between 1nm and 1.5nm based on controlling the speed that the dilute HF acid etches SiO2 grown on SiC.The standard samples were adopted to assist in analysis.The results indicate that the SiO2/4H-SiC interface simultaneously contains Si1+,Si2+,and Si3+.The ADXPS results suggest a layered model is suitable for describing the component distribution.An atom-level model of the transition region was established and the thickness of oxidation was calculated.The change of the transition components quantum and C-Vcurve indicate that the transition components directly affect the density interface trap.

Key words: SiO2/SiC interface,  4H-SiC, ADXPS,  interface state density, defect