Application of p-Channel Power VDMOSFET as a High Radiation Doses Sensor

This paper presents a comparative study of RADFETs and commercial p-channel power VDMOSFETs sensitivity to gamma-ray irradiation. Sensitivity was characterized by the threshold voltage shift determined from extrapolated linear region of transfer characteristics in saturation as a function of radiation dose. Sensitivity was followed in the dose range from 100 Gy to 500 Gy without and with + 10 V gate bias. Linear dependence between threshold voltage shift and radiation dose was established for components for which the gate bias during irradiation was + 10 V. Sensitivity of p-channel power VDMOSFETs is larger than the RADFETs, and it is a consequence of a larger concentration of fixed traps generated by gamma-ray irradiation. The mechanisms responsible for the threshold voltage shift during irradiation have been discussed as well. The fading of these components was also monitored at room temperature up to 24 hours and it was shown that it is larger in p-channel power VDMOSFETs then in RADFETs.