Influence Of The Laser Parameters On The Patterning Quality Of Thin-Film Silicon Modules

An analysis of the monolithical series connection of silicon thin-film modules with metal back contact fabricated by high speed laser ablation will be presented. Optically pumped solid state lasers with wavelengths of 1064 nm and 532 rim were used for the patterning steps. The near infrared laser is applied to pattern the TCO (P1) while the green laser is used for the ablation of the silicon layer stack (P2) and the back contact layer stack (P3). The influence of various laser parameters on the performance of amorphous and microcrystalline silicon modules was studied. In particular the back contact patterning and the Si removal can significantly affect the module efficiency. Non-optimized patterning conditions for P2 can lead to a high contact resistance, while the ablation of the ZnO/Ag back contact system can introduce shunts at the laser scribed line. Therefore, a criterion for flakeless patterning will be briefly introduced and the influence of flakeless back contact patterning on the electrical behavior of silicon single junction cells will be discussed.