Recovery treatment effects on gamma radiation response in electrically stressed power VDMOS transistors

The effects of electrical stress and post-stress recovery treatment (spontaneous and annealing) on gamma radiation response in power VDMOS transistors were investigated. It was shown that electrical parameters of electrically stressed devices, threshold voltage and channel carrier mobility, were more significantly recovered during annealing at 125°C as compared to spontaneous recovery at room temperature. On the other hand, annealing appeared less efficient than spontaneous recovery in terms of improving the radiation tolerance in electrically stressed devices. However, the most important finding is that, regardless of recovery treatment applied, electrical stress cannot be used to improve radiation tolerance of power MOSFETs.