Investigation of Total-Ionizing Dose Effects on the Two-Dimensional Transition Metal Dichalcogenide Field-Effect Transistors

Due to the excellent electrical properties, the emerging field-effect transistor (FET) based on two-dimensional transition metal dischalcogenide (TMD) is an excellent candidate for future space applications. However, the device performance is significantly impacted by total-ionizing dose (TID) effects. In this paper, the TID effects of TMD FETs are investigated comprehensively by means of developing a surface-potential based drain current model. Not only the radiation-induced trapped charges but also mobility degradation are incorporated into the proposed model. The model approach is demonstrated for a bottom-gated TMD FET, that simulation results are in good agreement with the experimental data. Based on the validity of the proposed method, the influence of TID effects on the TMD-on-insulator (TMDOI) FET is presented and discussed under different total dose levels. The results show that surface potential is strongly dependent on the oxide trapped charges, resulting in a major contribution to the negative shift of threshold voltage and the significant increase of leakage current. Besides, the interface trapped charges reduce the effective carrier mobility, which plays a dominant role on the decrease of transconductance and increase of subthreshold voltage swing. Finally, this paper gives insight into some possible mitigation techniques of TID effects on TMD FETs.