Gamma-ray irradiation-induced mobility enhancement of 4H-SiC NMOSFETs with a Ba-silicate interface layer

4H-SiC n-channel metal oxide semiconductor field effect transistors (NMOSFETs) with a Ba-silicate interface layer were irradiated with gamma-rays up to 850 kGy at room temperature. Above 600 kGy, the field effect mobility increased from 12 to 18 cm2 V−1 s−1. The narrower channel in the NMOSFETs enhanced radiation responses, such as mobility enhancement and threshold voltage shift. These results indicate that the edge of the channel significantly modifies the electrical characteristics.