Study of Si implantation into Mg-doped GaN for MOSFETs

In this paper we focus on activation and diffusion during annealing of silicon after implantation into Mg-doped GaN epitaxial layers. The Si diffusion was analyzed for different capping materials and compared to an uncapped sample. Investigation of the Si concentration obtained from secondary ion mass spectroscopy (SIMS) and comparison with calculation revealed several diffusion constants. Different diffusion behaviours at the surface were detected for different Si concentrations around the solubility of Si in GaN. Further, we found similar Si activation efficiencies in GaN for high and low fluences, after taking into account the compensation of electrons by the p-type background doping. In addition, we investigated the insulation between Si implanted islands in p-type GaN and the effect of additional Ar+ implantation.