Extending the limits of screen-printed metallization of phosphorus- and boron-doped surfaces

This work demonstrates low-ohmic electrical contacting of phosphorus- and boron-doped surfaces (textured and passivated) with maximum dopant concentrations of only Nmax≈2·1019 cm−3 by screen-printed and fired metallization. The achieved results using commercially available metallization pastes allow for a substantial extension of the limits in which screen-printed and fired metallization can be applied for solar cell fabrication. Despite the very low Nmax, the investigations reveal reasonably low specific contact resistances of ρC=(8±3) mΩ cm2 for a silver paste on alkaline textured, phosphorus-doped, and SiNx passivated surfaces, and ρC=(3.7±0.7) mΩ cm2 for a silver aluminum paste on alkaline textured, boron-doped, and Al2O3/SiNx passivated surfaces.