Structural stability and electronic levels of carbon-associated defects in SiO₂: First-principles study

Silicon Carbide (SiC) attracts much attention as the power semiconductor materials due to its superior material properties such as wide-band gap and high breakdown electric field [1]. In spite of the great materials properties, SiC has a big issue to be solved. That is the low electron mobility of SiC-MOS(Metal-oxide semiconductor) devices caused by the high density of interface traps (D_it). In particular, carbon-associated defects staying around the SiC/SiO₂ interface are the strong candidate for the D_it. In this study, we have clarified the structural stability and electronic levels of C-associated defects near the SiC/SiO₂ interface on the basis of the density-functional theory (DFT). Consequently, we have found that near the SiC/SiO₂ interfaces the carbon clustering is likely and some particular carbon defects cause defect levels near the conduction-band edge of SiC rendering them a strong candidate of the mobility killer.

[1] Y.-i. Matsushita and A. Oshiyama to be published in Jpn. J. Appl. Phys; arXiv:1810.09097 (2018).