Dynamic Performance Evaluation of N-channel MOSFET under Gamma Irradiation

Abstract

In this manuscript, the experimental studies for two groups, 2N7000 and BS107, of N-channel MOSFET are conducted. Each group, which have two devices from the same type, is exposed to dosages of gamma-ray ionizing radiation. The main objective of this study is to discuss the dynamic performance of these types under low dose ionizing radiation for purpose of usage as a low dose radiation dosimeter. Novelty of this study arisen from that the dynamic parameters such as threshold voltage, rise and fall times, the transconductance and capacitance between different device terminals are investigated. Because of gamma-ray irradiation, the surface and interface charges are arisen into MOSFET region. The threshold voltage is dependent on the MOSFET parameters, as it depends reversely on the oxide capacitance. From the obtained results, the channel width and length play an important role for determining all the dynamic parameters. One can notice that the majority of capacitances values are decreased. Consequently, the threshold voltage is decreased with the increase of radiation dose. From outcomes, the different transconductance values have different comportment according to the channel width and length into these adjacent regions. Generally, it tends to degrade with increasing the gamma-ray irradiation dose. The rise time tends to decrease while fall time tends to increase semi-linearly with increasing dosage values. From digital processing point of view, small shift in the rise or fall time will affect the pulse decision and then the information processing. Finally, one can conclude that n-channel MOSFETs under study not only have a specified response to gamma-ray radiation but also, they give a deterministic performance over the range of dose in this study. Therefore, the n-channel MOSFET under study - for both type number and dose-is a candidate to be a low dose dosimeter for gamma-ray radiation. The obtained dynamic response will be very important for any recent space or ionizing radiation environment and applications