Estimation of temperature impact on gamma-induced degradation parameters of N-channel MOS transistor

Abstract

The physical parameters of MOS transistors can be impressed by ionizing radiation and that leads to circuit degradation and failure. These effects require analyzing the basic mechanism that results in the buildup of induced defect in radiation environments. The reliable estimation also needs to consider external factors, particularly temperature fluctuations. I–V characteristic of the device was obtained using a temperature-dependent adapted form of charge-sheet model under heating cycle during irradiation with several ionizing dose levels at different gate biases. In this work, the analytical calculation for estimating the irradiation temperature impact on gamma-induced degradation parameters of N-channel MOS transistors at different gate biases was investigated. The experimental measurement was done in order to verify and parameterize the analytical model calculations. The results indicated that inserting irradiation temperature in the calculations caused a significant variation in radiation-induced MOS transistor parameters such as threshold voltage shift and off-state leakage current. According to the results, these variations were about 10.1% and 23.4% for voltage shifts and leakage currents respectively during investigated heating cycle for total dose of 20krad at 9V gate bias.