Atomic Coordination Analysis of Nitrogen Introduced in SiO2/ SiC Interface and SiO2 Layer by XAFS Measurement

Abstract

Although the nitridation by N2O or NO oxidation with annealing has been used in order to reduce interface trap density, the atomic location or coordination environment of nitrogen atom have been still unclear. In this study, we have investigated atomic coordination environment of nitrogen atom in both SiO2/SiC interface and SiO2 layer after nitridation by N2O annealing using XAFS measurements and ab initio multiple scattering calculations. Nitrogen in SiO2 layer was suggested to have the same atomic coordination environments as general SiON thin film. On the other hand, in SiO2/SiC region, nitrogen atoms were isolated and occupied the C-site of SiC structure, and it was confirmed that nitrogen atoms were surrounded by silicon atoms and strong Si-N bonds were formed in the interface region that was not eliminated by HF etching.