Development of Electronic Radiation Dosimeter Using Commercial Power pMOSFET

Abstract

When a metal oxide field effect transistor (MOSFET) is exposed to ionizing radiation, electron/hole pairs are generated in its oxide layer. The slow moving holes are trapped in the oxide layer of pMOSFET and appear as extra charges that change the characteristics of the transistor. The radiation-induced charges directly impact the threshold (turn-on) voltage of the transistor. This paper describes the use of the radiation-induced threshold voltage change of commercial power pMOSFETs as an accumulated radiation dose monitoring method. Two kinds of commercial p-type power MOSFETs were tested in a Co-60 gamma irradiation facility to see their capabilities as a radiation dosimeter. We found that the transistors showed good linearity in their threshold voltage shift characteristics with radiation dose. According to these results, a electronic radiation dosimeter using inexpensive commercial power pMOSFETs was developed for the first time. And these power pMOSFETs show good linearity in dose rate effect, room temperature annealing, and 100 iÉ thermal annealing for 48 hours.