Laser doping from as-deposited CVD layers for high-efficiency crystalline silicon solar cells

Laser doping from as-deposited CVD layers is a new and promising field for selective doping in solar cell processing. It allows for freely structured and adaptive doping with high-throughput. Challenging is the optimization of a variety of process parameters. In this work, we demonstrate the impact of laser parameters, such as fluence and sweep repetition, as well as thermal treatment i.e., tube diffusion, on passivation quality. Specifically, laser doping process dependence on the resulting doping profile and on iVOC level is investigated. Laser processing of solar cell precursors with a selective emitter and local BSF is shown to reach an iVOC of ~700 mV allowing for a high-efficiency level of >22.5% in industrial processing. The process flow in this case is suitable for a low-cost approach with reduced number of process steps.