Effects of total dose irradiation on the threshold voltage of H-gate SOI NMOS devices

Abstract

This work researched the impact of total dose irradiation on the threshold voltage of N-type metal oxide semiconductor field effect transistors (nMOSFETs) in silicon-on-insulator (SOI) technology. Using the subthreshold separation technology, the factor causing the threshold voltage shift was divided into two parts: trapped oxide charges and interface states, the effects of which are presented under irradiation. Furthermore, by analyzing the data, the threshold voltage shows a negative shift at first and then turns to positive shift when irradiation dose is lower. Additionally, the influence of the dose rate effects on threshold voltage is discussed. The research results show that the threshold voltage shift is more significant in low dose rate conditions, even for a low dose of 100 krad(Si). The degeneration value of threshold voltage is 23.4 % and 58.0 % for the front-gate and the back-gate at the low dose rate, respectively.