Behavior of substrate enhanced electron injection in advanced deep sub-micron NMOSFETs

Hot carrier degradation under conventional maximum substrate current Ib,max, electronic gate current Ig (HE) and substrate enhanced electron injection (SEEI) in advanced deep sub-micron NMOSFETs is studied. It is found that the interface trap generation is the dominant mechanism for hot carrier degradation under these three stress conditions. Furthermore, the behavior of SEEI under AC stress applied to the gate is investigated by charge pumping. The results indicate that the interface trap generation is also the dominant mechanism for hot carrier degradation under AC stress. However, due to the recovery of SEEI, the degradation of the electrical parameters for NMOSFETs at equally effective stress duration under AC stress is slightly less than that under DC stress. Finally, the recovery behavior of secondary impact ionization damage is discussed by using an on-the-fly technique and the charge pumping spot measurement technique. It is found that the passivation of the interface traps is directly responsible for the recovery of Idlin.