GaN p-n junction diode formed by Si ion implantation into p-GaN

²⁸Si⁺ implantation into Mg-doped GaN, followed by thermal annealing in N₂ was performed to achieve n⁺-GaN layers. The carrier concentrations of the films changed from 3 × 10¹⁷ (p-type) to 5 × 10¹⁹ cm^-3 (n-type) when the Si-implanted p-type GaN was properly annealed. Specific contact resistance (ρ_c) of Ti/Al/Pt/Au Ohmic contact to n-GaN, formed by ²⁸Si⁺ implantation into p-type GaN, was also evaluated by transmission line model. It was found that we could achieve a ρ_c value as low as 1.5 × 10^-6 Ω cm² when the metal contact was alloyed in N₂ ambience at 600 °C. Si-implanted GaN p-n junction light-emitting diodes were also fabricated. Electroluminescence measurements showed that two emission peaks at around 385 and 420 nm were observed, which could be attributed to the near band-edge transition and donor-to-acceptor transition, respectively.