Predictive simulation framework for boron diffused p+ layer optimization: Sensitivity analysis of boron tube diffusion process parameters of industrial n-type silicon wafer solar cells

A predictive simulation framework, combining process and device simulation, is developed in order to assist in BBr3 boron tube furnace diffusion process optimization for n-type silicon wafer solar cells. After an appropriate calibration, the influence of the tube diffusion process parameters (drive-in temperature, oxidation temperature, etc) on the final solar cell efficiency can be predicted. The key process parameters of BBr3 tube furnace diffusion are identified and their sensitivity on the final solar cell efficiency is calculated. An efficiency gain of 0.6% absolute to 20.0% is realized by optimizing only the front-side boron diffused layer of the front and back contacted cells. The efficiency is further improved to 20.9% by introduction of a local back-surface field design. A further optimization potential of up to 0.2% absolute is predicted by modifying the boron diffusion profile.