Impact of thermal NH₃-nitridation on dielectric properties of ultrathin Sio₂films

The dielectric properties of rapid thermally NH3-nitrided (RTN) ultrathin (∼5nm) SiO2 films have been investigated. High-field endurance characteristics indicate that after Fowler-Nordheim electron injection, both the low-field leakage current and electron trap density increase. Moreover, the oxide leakage is strongly dependent on the NH3-nitridation time. These results indicate that in ultrathin SiO2 the oxide leakage is a result of trap-assisted tunnelling, leading to a breakdown event when a critical trap density is reached.