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

Abstract

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 × 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 × 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 × 10 16 e / cm 2 , the drain current and transconductance decrease. The maximum transconductance for 1 × 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.