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

Abstract

28Si + implantation into Mg-doped GaN, followed by thermal annealing in N 2 was performed to achieve n +-GaN layers. The carrier concentrations of the films changed from 3×10 17 (p-type) to 5×10 19 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 cm 2 when the metal contact was alloyed in N 2 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.