Fabrication of p+-Si/p-diamond heterojunction diodes and effects of thermal annealing on their electrical properties

Abstract

We fabricate p+-Si/p-diamond heterojunction diodes by using surface-activated bonding and examine the electrical properties of Si/diamond interfaces by measuring current-voltage and current-voltage-temperature characteristics. We find that the electrical properties of heterojunction diodes are improved by post-bonding annealing at temperatures up to 873 K in terms of the ideality factor and reverse-bias current. Additionally, fabricated diodes also reveal thermal stability better than that of Cu/diamond Schottky diodes in terms of the rectification factor. The barrier height at Si/diamond bonding interfaces annealed at 873 K is estimated to be 0.55 and 0.66 eV by analyzing the relationship between the saturation current density and temperature and the reverse-bias characteristics at room temperature, respectively. These values are close to that obtained by assuming that no offset is formed in the vacuum level across the Si/diamond bonding interfaces (0.36 eV).