Investigation on the role of hole traps under NBTI stress in PMOS device with plasma-nitrided dielectric oxide

Negative bias temperature instability (NBTI) recovery for pure-SiO2 and plasma-nitrided oxide (PNO)-based PMOSFET has been investigated at room and below temperature. It is found that the generated hole traps in SiON dielectric under NBTI stress has a broadened energy distribution than that in SiO2 dielectric. This broadened maybe due to nitrogen related traps (K center) In SiON. The traps´ location in SiO2 and SiON are investigated by charge-pumping (CP) technique. In SiON most of Nitrogen-related traps located away from SiON/Si interface. The traps in SiO2 (E´ center) are at SiO2/Si interface. Based on the result of CP, nitrogen related traps located at a distance from SiON/Si interface (γ₀=10^-5s), we use the inelastic tunneling model to fit the degradation data of NBTI for PNO PMOSFET at 268K and 218K. Simulation results indicate a good agreement with the experimental data. These results show the nitrogen related traps play an important role in hole trapping under NBTI stress.