Effects of reoxidation on the hot-carrier immunity of 0.6 mu m MOSFETs with nitrided oxides

The effects of rapid thermal reoxidation (RTO) on the hot-carrier immunity of 0.6 mu m MOSFETs with thin ( approximately 13 nm) rapidly thermal nitrided (RTN) oxides is reported. The hot-carrier immunity is evaluated in terms of the threshold voltage shift, Delta V_th, and the transconductance degradation, Delta G_m/G_m(0), under worst case hot-carrier stress condition (with maximum substrate current I_sub,max). It is found that subsequent in-situ RTO of RTN oxides enhances the hot-carrier immunity, and this enhancement increases with RTO temperature. In addition, the natures of hot-carrier-induced damages in MOSFETs with RTO/RTN gate oxides are different from that with thermal SiO₂.