Investigations of hot-carrier-induced degradation for 700 V n-LDMOS transistor under different stress conditions

Abstract

AbstractThe hot-carrier reliability of a 700 V n-LDMOS transistor under different stress conditions is investigated in detail. For the high drain voltage (Vds) condition, the degradation of the saturate drain current (Idsat) is different from the on-resistance (Ron) degradation for the change of the dominated degradation mechanism. Moreover, the serious Ron degradation has identical variation tendency with substrate current (Isub) because the maximum impact ionization occurs at the surface of the drift region. However, for the high gate voltage (Vgs) condition, the most important degradation is the threshold voltage (Vth). We found that the Vth degradation has an exponential relationship with Vgs. In addition, it is also observed that the thick field oxide results in strong and rapid recovery of the Ron degradation.