Study of diffusion and thermal stability of fluorine ions in GaN by Time‐of‐Flight Secondary Ion Mass Spectroscopy

Abstract

AbstractThe diffusion properties of fluorine ions in GaN are investigated by means of Time‐of‐Flight secondary ion mass spectroscopy. Instead of incorporating fluorine ions close to the sample surface by plasma, fluorine ion implantation with an energy of 180 keV is utilized to implant fluorine ions deep into the GaN bulk, preventing the surface effects from affecting the data analysis. It is found that the diffusion of fluorine‐ions in GaN is a dynamic process, featuring a two‐step process. A defect‐assisted diffusion model is proposed to account for the experimental observations. Fluorine ions tend to occupy Ga vacancies induced by fluorine ion implantation and diffuse to vacancy rich regions. The fluorine ions become stable after continuous vacancy chains are significantly reduced or removed by thermal annealing. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)