Using a Shadow Mask during Gas-Phase Etching: A One-Step Patterning Method for Poly-Silicon Layers

This paper presents a convenient poly-silicon layer patterning technique, using a shadow mask during a gas-phase etching process. The etching is carried out at atmospheric pressure and delivers high throughput, single side processing and high selectivity, preserving the mask for multiple use and with potential for industrial application. This work was carried out in the context of the development of solar cell architectures beyond the standard TOPCon, where more sophisticated etching steps are required to accurately pattern poly-silicon layers across the wafer surface, in particular for the application of back contacted cells.