Radiation-induced defects in SiC-MESFETs after 2-MeV electron irradiation

The impact of radiation damage on the device performance of 4H-SiC metal Schottky field effect transistors, which are irradiated at room temperature with 2-MeV electrons, is studied. No performance degradation is observed by 1×1015e/cm2, while a slight increase of the linear drain current together with a decrease of the threshold voltage are noticed for 1×1016e/cm2. The degradation for low electron fluence is mainly attributed to the radiation-induced decrease of the Schottky barrier height at the gate contact. For exposures over 1×1016e/cm2, the drain current and transconductance decrease. The maximum transconductance for 1×1017e/cm2 is only 18% of the value before irradiation. Although no electron capture levels are observed before irradiation, three electron capture levels (E1–E3) are induced after irradiation. The observed increase of the channel resistance is due to the induced lattice defects creating electron traps.