Predictive simulation of doping processes for silicon solar cells

We present improvements and calibrations for boron and phosphorus doping models, which allow highly predictive simulations of various doping processes used for solar cells. Besides boron doping from a boron tribromide (BBr3) source and phosphorus doping from a phosphorus oxychloride (POCl3) source, oxidation and implantation processes for solar cell applications are simulated. The use of one set of model parameters for different doping techniques improves the calibration quality, ensures the generality of the model and allows a separation of the physical mechanisms influencing the dopant diffusion process. The simulations are compared to measured depth profiles of a large number of processes, which vary in time and temperature. In addition to excellent agreement to measured doping profiles, the sheet resistances and emitter depths of almost hundred diffusion processes are in good consistency with the simulations. Multiple experiments to optimize doping profiles regarding the shape, surface concentration or sheet resistance can thus be avoided.