Transconductance degradation and interface state generation in metal-oxide-semiconductor field-effect transistors with oxynitride gate dielectrics under hot-carrier stress

The hot-carrier immunity of submicrometer (0.8 μm) n-channel metal-oxide-semiconductor field-effect transistors with thin (∼8.6 nm) oxynitride gate dielectrics prepared by rapid thermal reoxidation (RTO) of rapidly thermal nitrided (RTN) SiO2 has been studied. The hot-carrier immunity was evaluated in terms of hot-carrier-induced transconductance degradation (ΔGm/Gm0) and interface state generation (ΔDit/Dit0) which was measured by using charge pumping current (Icp) measurement. It is found that for improved device performance and reliability, there exists an optimum RTO condition for a given RTN SiO2. In addition, a strong correlation between ΔDit/Dit0 and ΔGm/Gm0 has been observed.