Scribe Width Optimization of Absorber Laser Ablation for Thin-film Silicon Solar Modules

The scribe width reduction of the absorber removal process for the integrated series connection of thin-film silicon solar modules was investigated with laser-induced back-side ablation. Depending on the used scribing beam spot radius and absorber thickness changes of ablation behavior lead to limitations of the scribe width reduction. The influence of the laser processes on the electrical properties between front- and back-contact was characterized with Transmission Line Method measurements. The values of the interconnection resistance between front- and back-contact are used in electrical calculations to estimate the optimal trade-off between increase of active cell area with thinner scribe lines and the increase of series resistance losses from interconnection resistance formation. Calculations predict a similar to 1% relative decrease of module losses for the optimized processes compared to commonly used processes from industry.