Effects of radiation-induced defects on device performance in electron-irradiated SiC-MESFETs

The impact of radiation damage on the device performance of 4H-SiC metal semiconductor field effect transistors (MESFETs), which are irradiated at room temperature with 2-MeV electrons and 20-MeV protons, is studied. Different degradation behaviour with increasing fluence is observed for electron and proton irradiation. The degradation for low electron fluence is mainly attributed to the radiation-induced decrease of the Schottky barrier height at the gate contact. While no electron capture levels are observed before irradiation, three electron capture levels (E1, E2 and E3) are induced after irradiation. The observed increase of the channel resistance is due to the induced lattice defects creating electron traps.