Enhanced Radiation Tolerance of MoS2 FET via Al2O3 Insertion on SiO2 Dielectric

Molybdenum disulfide (MoS₂) combines a tunable bandgap and high carrier mobility, making it promising for nanoelectronics. Its inherent radiation tolerance further promotes the development of radiation-hardened devices for extreme environments, such as outer space exploration. Although research has been conducted on the damage mechanisms of MoS₂ field-effect transistors (FETs) under ionizing irradiation, studies on the modulation of charge trapping through gate dielectric engineering to enhance their radiation tolerance remain relatively scarce. In this work, we designed back-gated MoS₂ FETs by inserting a traditional high-κ dielectric alumina (Al₂O₃) between the MoS₂ and silicon dioxide (SiO₂), forming a MoS₂/Al₂O₃/SiO₂ structure, and compared them with MoS₂/SiO₂ FETs. The devices were subjected to 200 keV proton irradiation at a dose of 1 × 10¹⁴ cm^–2, and the comparative results show that the MoS₂ FET with Al₂O₃ exhibits significantly enhanced radiation tolerance. This improvement is primarily attributed to the high dielectric screening effect of Al₂O₃, which greatly reduces Coulomb scattering, thereby not only mitigating displacement damage in the MoS₂ channel but also effectively suppressing the generation of interface and oxide trapped charges. Therefore, dielectric engineering serves as a critical strategy to provide support for the development of two-dimensional electronic systems that can operate reliably in extreme radiation environments.