Radiation Hardness of 4H-SiC JFETs in MGy Dose Ranges

Abstract

Silicon carbide junction field effect transistors (SiC JFETs) were irradiated with gamma-rays up to 9 MGy (H2O). With increasing dose, apparent shift of drain current-gate voltage (ID-VG) curves to negative voltage side as observed for SiC metal oxide semiconductor (MOS) FETs did not take place. No significant difference is observed between drain and gate leakage currents of irradiated JFETs. This strongly indicates that defects as leakage paths were introduced into not bulk region but the interface between bulk and the passivation layer of SiO2. While, the transfer characteristics including threshold voltage and transconductance were slightly changed compared with the pristine sample. After drain voltage (VD) was abruptly applied to 6 V, ID at VG= 0 V increased slowly as a function of time. This indicates that variation of transfer characteristics is attributed to capture and emission process at defects generated in channel region.