Technology path to the industrial production of highly efficient and thin c-Si solar cells
Higher efficiencies and thinner wafers are the most prominent approaches in solar cell technology to significantly reduce the Wp-price. Plasma etching, dielectric passivation, fast thermal and laser processing have been identified as key technologies to reach these targets. This paper gives an up-to-date overview of the achievements in improving and upscaling these technologies at Fraunhofer ISE. A complete dry and inline solar cell process with a textured front and passivated surfaces is proposed. A key to this process is the laser fired contact technology, which has been successfully transferred to a new system, enabling laser process times of just a few seconds while maintaining efficiencies of 21% on high-efficiency cell structures. In-line diffusion using the walking string transport yields higher carrier lifetimes in comparison to the standard metal belt systems enabling highly-efficient cell processing.