Methods to pattern diffusion layers in solar cells and solar cells made by such methods

Abstract

Methods exploiting a Self Aligned Cell (SAC) architecture for doping purposes, use the architecture to direct the deposition and application of either a dopant or a diffusion retarder. Doping is provided in regions that will become metallization for conducting fingers. Dopant may be treated directly into metallization grooves. Or, diffusion retarder may be provided in non-groove locations, and dopant may be provided over some or all of the entire wafer surface. Dopant and metal automatically go where desired, and in register with each other. The SAC architecture also includes concave surfaces for light absorbing regions of a cell, to reduce reflection of light energy, which regions may also be treated with dopant in the concavities, to result in semi-conductor emitter lines. Alternatively, diffusion retarder may be treated into the concavities, leaving upper tips of ridges between the concavities exposed, thereby subject to deeper doping.