Leakage Performance of 4H-SiC CMOS Logic Circuits After Gamma Irradiation

In this letter, the leakage performances of 4H-SiC CMOS devices, as well as inverter (INV) and NOR logic gate circuits, are evaluated after being exposed to irradiation. It has been observed that the output voltage swing of the SiC INV and NOR gate circuits decreases evidently and large leakage currents appear at the total irradiation dose of 300kGy. The mechanism of leakage current is revealed by conducting Emission Microscope test and analysis of leakage paths based on the layout. The inversion layer forms on the P-epi surface under the polysilicon gate and VDD metal after irradiation, which causes the electron leakage current flowing from N-well to P-epi. At last, suggestion on hardening 4H-SiC CMOS gate circuits is given.