Interpretation of 60Co radiation effects in metal-oxide semiconductors in terms of the mobility and interface trap density with a drain current-gate voltage model

The voltage-dependent current is a crucial parameter for determining the electrical properties of microelectronic devices. In this study, we aimed to extend a generic dc model to successfully explain the drain current (I-d) for metal-oxide semiconductors (MOSs) and thin-film transistors (TFTs) based on the gate voltage (V-g), where the threshold voltage (V-th) could also be obtained from this model in a nature manner. This dc model meets the requirements for compact modeling, including modeling computer circuit simulators. The application of this model to p-type MOS and n-channel MOS transistors irradiated by Co-60 showed that this generic dc model covers all the regimes for MOS or TFT linear and saturation operation above V-th sub-threshold, and reverse biasing. In addition, the radiation-induced shift location of V-th was found using this model. The mathematical relationships are defined between the V-th and radiation dosage (D), so the Co-60 enhancement effect on the mobility, mu, and interface trap density are also successfully explained by D.