US Patent 9401450 Solar cell emitter region fabrication using ion implantation

Methods of fabricating solar cell emitter regions using ion implantation, and resulting solar cells, are described. In an example, a method of fabricating alternating N-type and P-type emitter regions of a solar cell involves forming a silicon layer above a substrate. Dopant impurity atoms of a first conductivity type are implanted, through a first shadow mask, in the silicon layer to form first implanted regions and resulting in non-implanted regions of the silicon layer. Dopant impurity atoms of a second, opposite, conductivity type are implanted, through a second shadow mask, in portions of the non-implanted regions of the silicon layer to form second implanted regions and resulting in remaining non-implanted regions of the silicon layer. The remaining non-implanted regions of the silicon layer are removed with a selective etch process, while the first and second implanted regions of the silicon layer are annealed to form doped polycrystalline silicon emitter regions.