Degraded CMOS hot carrier life time-role of plasma etching induced charging damage and edge damage

There are two different types of damage resulting from plasma etching (oxide charging damage and plasma edge damage) which can degrade the reliability of CMOS devices. The oxide charging damage is due to plasma induced Fowler-Nordheim current flowing through gate oxide, while edge damage is due to direct plasma exposure during the poly-Si overetch period. This paper addresses the influence of plasma etching-induced damage on device susceptibility to hot-carrier (HC) degradation. The role of oxide charging damage and that of edge damage are isolated and characterized for both n-channel and p-channel MOS devices, and the corresponding dependence of HC lifetime is analyzed. Finally, the effect of plasma damage on HC degradation of ring oscillators is studied.