High speed laser processing for monolithical series connection of silicon thin‐film modules

Abstract A detailed analysis of the monolithical series connection of silicon thin‐film modules with metal back contact fabricated by high‐speed laser ablation will be presented. In this study, optically pumped solid‐state lasers with wavelengths of 1064 nm and 532 nm were used for the patterning process. The influence of various laser parameters on the performance of amorphous and microcrystalline silicon modules will be discussed. In particular, the line‐scribing parameters for a TCO and Ag back contact system was analyzed in detail, since it is the most critical patterning step. A detailed description of the back contact ablation process will be presented and a criterion for flakeless patterning was defined. Finally the influence of the back contact patterning on the electrical behavior of silicon single junction cells was studied. The dark current density versus back‐contact patterning line length was analyzed by means of a developed SPICE (simulation program with integrated circuit emphasis) simulation model. Copyright © 2007 John Wiley & Sons, Ltd.