Research on Radiation-Induced Threshold Voltage Shifts in Power MOSFET Based on Charge-Pumping Method

Total ionization dose experiment was carried out using Co-60 Gamma-irradiation source and radiation-induced threshold voltage shifts in power MOSFET were measured. Interface-trapped minority carriers which generating recombination current were measured based on charge pumping method, and contributions of both radiation-induced interface and oxide traps to threshold voltage shift were separated. An optimal value was obtained by comparing influence of pulse base level, peak to peak amplitude on charge pumping current I
_cp
and then applied to the extraction of radiation-induced interface-trap density. It was found that interface-trap density increased from 3.9 ×10
⁹
cm
^-2
to 2.5 × 10
¹¹
cm
^-2
after irradiation and the threshold voltage shift is less than 1V.