Temperature dependence of substrate current and hot carrier-induced degradation at low drain bias

Abstract

Temperature dependence of substrate current (Isub) and hot carrier lifetime in sub 0.25 /spl mu/m NMOS devices has been evaluated at elevated temperatures. Unlike conventional behaviour, for scaled devices Isub is found to increase with temperature at low drain bias. The transition point to the new behaviour is found to be bias and temperature dependent. The correlation between hot carrier lifetime and Isub has been found to still hold in the new regime. At Vd=1.5 V, this results in 4/spl times/ lower lifetime at 125 C versus 25 C. The lucky electron model is found not to explain the new observations. These findings are consistent with previously reported results on Isub at reduced temperatures and the modeling of statistical distribution of carrier energy at low drain bias.