Suppression of nitridation-induced interface traps and hole mobility degradation by nitrogen plasma nitridation

Abstract

The impact of nitrogen plasma nitridation on the interfacial quality of ultrathin oxides (1.8 and 2.6 nm) have been investigated and compared with NO nitridation. It is found that plasma-nitrided oxides are more immune to nitridation-induced degradation of channel hole mobility, and have lower intrinsic interface-trap density as compared to NO-nitrided oxides. In addition, plasma-nitrided oxides can further suppress hole mobility degradation induced by boron penetration. The superior performance of nitrogen plasma nitridation is attributed to its capability of incorporating a high level of nitrogen at the top oxide surface, while keeping the Si-SiO2 interface intact.