Realizing narrow contact fingers with low lateral resistance is a major goal for the front-side metallization of silicon solar cells. The formation of screen-or stencil-printed contact fingers is governed by a variety of influencing factors. One of these factors is the surface roughness of the textured silicon wafer. However, only a few investigations have been carried out to investigate this impact in detail. In this study, the influence of arithmetical mean roughness R a of four differently textured wafer surfaces on contact finger geometry and lateral finger resistance, as well as optical and electrical losses, has been investigated. It will be shown that texture roughness has a considerable impact on the properties of the front-side grid. Narrower contact fingers could be realized on the smoothest texture, leading to a current density gain of Δj sc = +0.27 mA/cm 2 . On the other hand, increasing texture roughness has affected the amount of transferred paste and, thus, has led to a lower lateral finger resistance R L . Thus, contact fingers on the roughest texture have benefited from a fill factor gain of ΔFF = +0.24 % ab s . A sensitivity analysis of both impacts has shown that the current density gain has overcompensated the fill factor loss. Thus, textures with a small roughness are beneficial with respect to the formation and electrical properties of stencil-printed front-side grids.

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This work highlights present research and mass production results of wet‐chemical solutions for industrial edge isolation of silicon solar cells, aiming for a reduction of nitric acid consumption and production costs as well as a simultaneous increase in efficiency. All processes are applied to either industrially passivated emitter and rear contact (PERC) or tunnel oxide‐passivated contact (TOPCon) solar cells. Herein, a review of different edge isolation techniques in the history of silicon solar cell processing is presented. Subsequently, novel wet‐chemical approaches are focused on, namely 1) HNO3‐reduced edge isolation (InOxSide Fusion), 2) HNO3‐free edge isolation (InOxSide Blue), and 3) batch cluster solution—a combination of an acidic inline and an alkaline batch tool for emitter edge isolation of PERC and TOPCon solar cells. For each of the approaches, cell results and total cost of ownership estimations are presented. Based on all findings, a comprehensive discussion between inline versus batch‐cluster processing is presented. All investigations are performed on industrial equipment, wafer sizes, and a solar cell efficiency level of above 23%.

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