Ultrathin nitrided gate dielectrics by plasma-assisted processing

Ultrathin (<3 nm) gate dielectrics made by plasma nitridation of SiO2 films were investigated by a combination of physical (ellipsometry, nuclear reaction analysis, medium energy ion scattering, and atomic force microscopy) and electrical (capacitance-voltage, current-voltage, and constant voltage stress) methods. Results showed that this manufacturing process offers good thickness uniformity and reduced leakage current. However, there is a flatband voltage shift and reduced peak mobility. Both of the detrimental effects may be large at high nitrogen concentrations. In addition, plasma induced damage may effect oxide reliability properties.