Advanced Fine Line Printing with Glass Stencils: Achieving Metal Contact Fingers Below 10 µm

For high-efficiency solar cells, such as Si-III-V tandem solar cells, implementing narrow contact fingers is essential for achieving optimal conversion efficiencies. By achieving narrower contact fingers without compromising electrical performance, more sunlight reaches the active areas of the cell, thus reducing front-side shading and enhancing overall energy conversion efficiency. In this work we demonstrate a proof of principle for a novel low-temperature metallization process using glass stencils to print ultra fine line contacts. The narrowest contacts achieved have a width of w_f = 8.4 ± 1.3 with an aspect ratio of 〖AR〗_opt = 0.19 ± 0.05. Through optimization described in this work, contact fingers with w_f = 9.7 ± 0.6 µm and a substantially greater aspect ratio of 〖AR〗_opt = 0.45 ± 0.1 could be achieved. To realize these ultra fine line fingers, glass stencils with tailored aperture channels were realized using a two-step Laser Induced Deep Etching (LIDE) process that enables complex three-dimensional aperture channel geometries.