Optimization of Front and Rear Surface Dielectric Passivation Layers for Ion Implanted PERC Solar Cells

Ion implantation is an alternative doping method providing a controlled emitter profile and manufacturing simplicity for PERC solar cells. SiNx:H and SiOxNy:H layers deposited by the PECVD system are common dielectric layers used as surface passivation, antireflective coating (ARC), and capping layers at the front and rear surfaces of PERC solar cells. Here, we report and discuss the dielectric stacks having different optical and electrical properties at the front and rear surfaces of the ion implanted PERC solar cells. To investigate the optical loss at the front side, we first simulate the ARC layers based on the optical parameters, which we measured on our dielectrics by spectroscopic ellipsometry. Besides, the rear passivation stacks were analyzed on symmetrically fabricated samples by iV(oc) measurements. Additionally, we fabricated ion implanted PERC solar cells with various SiNx:H and SiOxNy:H stacks to show the influence of the front and rear dielectric layers on the cell performances. Our results demonstrate that the implanted PERC solar cells can be improved with an electrical and optical optimization of dielectrics on both the front and rear surfaces. The champion PERC solar cell with the ion implanted emitter exhibits a PCE of 20.25%.