Effect of Au/Ni/4H–SiC Schottky junction thermal stability on performance of alpha particle detection

Au/Ni/n-type 4H–SiC Schottky alpha particle detectors are fabricated and annealed at temperatures between 400℃ and 700℃ to investigate the effects of thermal stability of the Schottky contact on the structural and electrical properties of the detectors. At the annealing temperature of 500?C, the two nickel silicides(i.e., Ni_(31)Si_(12) and Ni_2Si) are formed at the interface and result in the formation of an inhomogeneous Schottky barrier. By increasing the annealing temperature,the Ni_(31)Si_(12) transforms into the more stable Ni_2Si. The structural evolution of the Schottky contact directly affects the electrical properties and alpha particle energy resolutions of the detectors. A better energy resolution of 2.60% is obtained for 5.48-MeV alpha particles with the detector after being annealed at 600℃. As a result, the Au/Ni/n-type 4 H–SiC Schottky detector shows a good performance after thermal treatment at temperatures up to 700℃.