Recovery of threshold voltage after hot-carrier stressing

The recovery of threshold voltage due to high drain or gate voltage and the effects of hot-carrier stressing on the drain breakdown voltage of MOSFETs have been studied. A high oxide field causes slow recovery through tunneling detrapping of electrons in both p- and n-MOSFETs. For n-MOSFETs the mechanism of fast recovery is low-level hole injection at high V/sub D/. Hot-carrier stressing at high V/sub G/ causes the drain breakdown voltage to decrease (walk-in). This results in enhanced hold injection, thus increasing the rate of subsequent recovery of V/sub t/. The breakdown voltage increases and then decreases when stressed at low gate voltages.>