Study on microstructure and sample modification of laser ablation processes

Laser based processes are widely-used in the photovoltaic industry to prepare precisely local sample properties. They are used in example for drilling, separation, doping, creating local contacts on the cell back side and selective ablation of passivation layers for PERC solar cells [1]. We conducted a SEM based study on selective laser-ablation process variations to elucidate small morphological details and defects which can be separated and characterized like shown by different groups [e.g. 2-4]. Variations of laser parameters exhibited different surface modifications. Optimum process setups should show a complete and homogeneous ablation of the dielectric layer(s) and no silicon-substrate damage.