Mg-annealed anode contacts to reduce the on-resistance of GaN pn diodes formed via Mg implantation and ultra-high pressure annealing

Drive-in diffusion of implanted Mg during ultra-high pressure annealing (UHPA) leads to low surface acceptor concentrations. This favors p-type Schottky contact formation, which severely increases the on-state resistance of Mg-implanted pn diodes (PNDs). This work aims to reduce the resistance of contacts to Mg-implanted p-GaN by incorporating Mg deposition and annealing into the contact stack, achieving a rectification ratio over 10 12 , a current density above 1 kA/cm 2 and a record-low differential specific on-resistance (R ON ) of 0.65 mΩ.cm 2 in Mg-implanted PNDs, offering a potential solution for improving the performance and manufacturability of vertical GaN devices that require contacts to Mg-implanted p-GaN.