Abstract
This thesis study about optoelectric properties and thermal stability of p-GaN reflective ohmic contacts Ti (2nm) / Ag (150nm), AgTi (2 at%), AgTi (4 at%), Co(2nm) / Ag (150nm), AgCo (2 at%), AgCo(5 at%) and AgNi(2 at%) seven specimens which are prepared by due electron guns evaporation.We discuss the effect, including light reflectivity, sheet resistance of the metal thin film, specific contact resistance and thermal stability, on the optoelectric properties of AgTi, AgCo and AgNi alloy reflective ohmic contacts, be influenced by different alloy composition, different annealing methods, including furnace annealing and rapid thermal annealing.The result show annealed AgCo(2 at%) and AgNi(2 at%) could suppress the agglomeration of Ag film. The specific contact resistance was 3.4 × 10-4 and 1.1 × 10-4 Ω-cm2, reflectance was 94% and 92% at 460 nm, and sheet resistance of metal film was both 0.5 Ω/□ for annealed AgCo(2 at%) and AgNi(2 at%) at 500℃ in air ambient for 10 min. Both AgCo(2 at%) and AgNi(2 at%) reflective ohmic contacts showed good thermal stability.