-ray irradiation effects on the characteristics of p-type 6H-SiC schottky diodes

Sudjadi, U.; Oshima, Takeshi; Iwamoto, Naoya; Hishiki, Shigeomi; Kawano, Katsuyasu*

-ray irradiation effects on the characteristics of P type 6H-SiC Schottky diodes ware studied. Schottky diodes were fabricated on P-type 6H-SiC epitaxial layers grown on P type 6H-SiC substrate. The doping concentration of the epi-layer is 5.910/cm. The ohmic contact of the back side were fabricated by the evaporation of Al/Ni and subsequent annealing at 1100C for 60 sec in vacuum ambient. Ni Schottky contacts with diameters of 30300 m were formed on the P type epi-layer using a photolithography technique. The samples were irradiated with -rays up to 182.7 kGy at room temperature. During the irradiation, no bias was applied to diodes. The dose rates of irradiation were 0.51.0 Mrad/hour. The electrical characteristics of the diodes were evaluated before and after irradiation. As the results, the leakage current density decreases with increasing absorbed dose up to 35 kGy, and the saturation of the leakage current density is observed above 35 kGy. For the Saturation current density, the values decrease with increasing up to 35 kGy, and no significant change is observed above 35 kGy.