We derive a diffusion flux and diffusion equation step by step, starting with a rough sketch one to a practical one. The flux is described with the paring with point defects, and the dependence of diffusion coefficients on doping concentration is emerged. We can predict diffusion profiles by solving the equation.
Keywords: Ion implantation, diffusion, diffusion flux, diffusion equation, diffusion coefficient, point defects, doping concentration, lattice sites, jumping frequency, electric field, mobility, Einstein’s relationship, interstitial Si, intrinsic carrier concentration, statistic mechanism.
