Role of e-e scattering in the enhancement of channel hot carrier degradation of deep sub-micron NMOSFETs at high VGS conditions

It has been reported in the literature (Rauch et al., 1998; Wang-Ratkovic et al., 1997; Su et al, 1996; Li et al., 1999) that in deep submicron NMOSFETs the worst channel hot carrier (CHC) degradation is not near the peak substrate current (as predicted by the lucky electron model (Hu et al., 1985)), but at the V_GS=V_DS bias condition. We propose a new CHC model based on an electron-electron scattering induced hot carrier mechanism, that explains the worsening of the HC damage at high V_GS and agrees well with the HC lifetime measured over the moderate-to-high gate voltage range and a wide L_EFF range. The predicted quadratic source current dependence of HC lifetime at mid V_GS/V_DS , evolving into a cubic dependence at high V_GS/V_DS , matches the observed behavior well