Study of the improvement of Ni/Au ohmic contact to p-GaN by Pt~+ implantation

Pt+ ions were implanted at the interface of p-GaN /Ni/Au(5/10nm),and then the sample was treated with rapid thermal annealing(RTA) in air for 5min.The ohmic contact characteristics between the metal electrode and p-GaN got obviously improved,and the specific contact resistance(ρc) reduced from 10-1Ω·cm2 order to 10-3Ω·cm2 order.The effect of different implantation dose,i.e.5×1015,1×1016,2×1016,and anneal temperature,i.e.300,500,700℃,on ρc is investigated.The lowest ρc,i.e.3.555×10-3Ω·cm2,is achieved after annealing in air at 300℃ in air for 5min with 1×1016cm-2 Pt+ ion implantation.The corresponding mechanisms of the improvement of ohmic contacts by Pt+ ion implantation are discussed.