Understanding coupled oxide growth and phosphorus diffusion in POCl3 deposition for control of phosphorus emitter diffusion

Effective control of diffused phosphorus profiles in crystalline silicon requires detailed understanding of the doping process. We analyze concentration profiles within the deposited phosphosilicate glass (PSG) for a range of POCl₃ conditions and develop a model to account for the experimentally observed time dependence of PSG thickness and dose of phosphorus in Si. A simple linear-parabolic model cannot fully explain the kinetics of thickness and dose; while an improved growth model including oxygen dependence and dose saturation gives better fits to the experiments. We further couple the growth model with phosphorus diffusion and deactivation models in silicon and provide full modeling of the POCl₃ doping process.