It was recalled that N implantation was used to control gate oxide thickness. By varying the N dose, various gate oxide thicknesses could be obtained by using the same process. However, although it was accepted that N retarded gate oxidation kinetics, the mechanism was not yet well understood. Since the retardation in oxide growth was due to the diffusion of N and its subsequent incorporation at the Si/oxide interface, the study of the diffusion behavior of N in Si became important. Furthermore, it was also necessary to determine how this diffusion behavior affected oxide growth. Models were developed to explore these issues. The diffusion model was based upon ab initio results, and was compared with experimental results at 2 temperatures. The oxide reduction model was based upon the diffusion of N to the surface. The surface N was coupled to the surface reaction rate of Si and O such as to moderate oxide growth.

Physical Integrated Diffusion-Oxidation Model for Implanted Nitrogen in Silicon. L.S.Adam, M.E.Law, O.Dokumaci, S.Hegde: Journal of Applied Physics, 2002, 91[4], 1894-900