Hot carrier degradation on n-channel HfSiON MOSFETs: effects on the device performance and lifetime

A study of hot carrier reliability of n-channel SiON and HfSiON MOSFETs with poly-Si gate is proposed. During hot carrier stress, both interface state and bulk defect generation were observed. A comparison for different stress conditions, i.e., maximum substrate current and maximum electron injection, is provided. HfSiON MOSFETs show longer lifetime, if defined in terms of device performance, than MOSFETs with SiON with similar equivalent oxide thickness. Finally, we show that hot carrier degradation strongly reduces gate stack lifetime with respect to the Fowler-Nordheim stress commonly used to evaluate the time dependant dielectric breakdown.