Lifetime Estimation in NBT Stressed P-Channel Power VDMOSFETs

Threshold voltage shifts observed in commercial p-channel power VDMOSFETs during the NBT stressing are fitted using stretched exponential equation in order to estimate the device lifetime and discuss the impact of stress conditions and choice of extrapolation parameters. Excellent agreement found in later stress phases allowed for an accurate estimation of device lifetime for the lowest stress voltage applied, saving the time required for an extended experiment. More realistic lifetime estimates also are expected in the case of lower stress voltages, which additionally justify the need for using stretched exponential or some other suitable fit