The isochronal annealing of irradiated n-channel power VDMOSFETs

The threshold voltage, VTVT, as well as threshold voltage shift, ΔVTΔVT, and its components, the component of threshold voltage shift due to radiation-induced fixed traps in the oxide, ΔVftΔVft, and the component of threshold voltage shift due to radiation-induced switching traps near and at gate oxide/substrate interface, ΔVstΔVst, are investigated, and fitted very well. The behavior of unannealed fraction of fixed traps during isochronal annealing is also considered. The proposed model describes unannealed fraction very well, and allows the prediction of fixed traps behavior at higher temperature. The number of defect types that are observably active during an isochronal temperature range could be found by this model, showing that isochronal annealing is competitive with isothermal annealing, which is widely used, but much more time consuming.