Gas Phase, Selective Etching of Poly-Silicon for Layer Patterning

This paper will present patterning process developments using a single-side, gas-phase etching process based on the thermal reaction of poly-Silicon and a spontaneous etching Halogen gas, that results in a high etching selectivity between layers, and a high etching rate. This work was carried out in the context of the development of solar cell architectures beyond PERC and TOPCON, where more sophisticated etching steps are required in order to accurately pattern poly-silicon layers across the wafer surface.