Analysis on the Rapid Recovery of Irradiated VDMOSFETs by the Positive High Electric Field Stress

High electric field stress (HEFS) and annealing effects on irradiated (by
⁶⁰
Co γ-ray) vertical double-diffused MOSFETs (VDMOSFETs) are investigated. The behaviors of the oxide-trapped charges and interface traps during the stress are measured by using a simplified midgap technique. Rapid recovery of the threshold voltage (V
_th
) for the irradiated VDMOSFET is observed under a positive high electric field stress (PHEFS). The results show that the densities of oxide-trapped charges and interface traps decreased more rapidly for the PHEFS than that for postirradiation annealing. Repeated irradiation results of PHEFS-recovered VDMOSFETs indicate the possibility of reusing the irradiated VDMOSFETs.