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

摘要

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 x 10~(15) e/cm~2, while a slight increase of the linear drain current together with a decrease of the threshold voltage are noticed for 1 x 10~(16) e/cm~2. 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 x 10~(16) e/cm~2, the drain current and transconductance decrease. The maximum transconductance for 1 x 10~(17) e/cm~2 is only 18% of the value before irradiation. Although no electron capture levels are observed before irradiation, three electron capture levels (E_1-E_3) are induced after irradiation. The observed increase of the channel resistance is due to the induced lattice defects creating electron traps.