Effects of elevated-temperature bias stressing on radiation response in power VDMOSFETs

The effects of pre-irradiation elevated-temperature bias stressing on radiation response of power VDMOSFETs have been investigated. Larger irradiation induced threshold voltage shift in stressed devices and considerable mobility reduction in unstressed devices have been observed. The underlying changes of gate oxide-trapped charge and interface trap densities have been calculated and analysed in terms of the mechanisms responsible for pre-irradiation stress effects.