Experimental and numerical investigation of the electrical characteristics of vertical n-p junction diodes created by Si implantation into p-GaN

Vertical n-p junction diodes were fabricated by Si⁺ ion implantation into Mg doped p/p⁺ GaN, followed by rapid thermal annealing at 1260degC in NH₃/N₂ for 30 s. Implantations were performed at 40, 60 and 80 keV and circular contacts on the n-region were fabricated with various diameters between 100 and 600 mum. Light emission from the periphery of the contact under forward bias conditions confirmed the existence of an n-p junction. Current-voltage characteristics revealed rectifying behaviour associated with n-p junction. 2-Dimensional Sentaurus Devicetrade was used to simulate the device. Current density distribution indicates high current near the peripheral region and it appears that the performance of the device is not determined by the implantation conditions. Further optimisation of the vertical structure is required to improve the device performance.