Schottky barrier heights of semi-insulating 6H-SiC irradiated by high-dose γ-rays

The 6H-SiC radiation detector samples were irradiated by 60Co γ-rays. The irradiation was performed with dose rates of 5 and 15 kGy/h for 8 hours, respectively. Metal/semiconductor contacts on the surface were fabricated by using a thermal evaporator in a high vacuum condition. The 6H-SiC detectors have metal contacts of Au(200 nm)/Ni(30 nm) at Si-face and of Au(200 nm)/Ti(30 nm) at C-face. I–V characteristics of the 6H-SiC radiation detectors were measured by using the Keithley 4200-SCS parameter analyzer with self-voltage sources. From the I–V curve, we analyzed the Schottky barrier heights (SBHs) on the basis of the thermionic emission theory. As a result, the 6H-SiC semiconductor detector showed similar SBHs independent of the dose rates of the irradiation with 60Co γ-rays.