ADVANCED LASER PATTERNING AND METALLIZATION TECHNOLOGY FOR MWT PERC SI SOLAR CELLS

摘要

Within the framework of the US DoE funded FPACE project several advancements to a p-type PERC cell concept have been studied. In a first step the potential to combine a PERC process with a metal wrap through (MWT) approach - taking advantage of the back side passivation to shield the wrapped-through front contact - has been evaluated. The possibility of using an extrusion process to connect the MWT vias on the front side of the cell has been studied. A process of local line width modulation from 60 to 160 μm has been developed by PARC to allow for a reliable alignment between the contact fingers and the through connections. Finally the potential of combining the improved internal reflection and rear surface passivation of a PERC cell with a reduced front side recombination by employing local laser diffusion has been investigated. A detailed laser parameter study has been conducted and the laser parameters have been evaluated in regards to their impact on cell performance and phosphorous doping profile.