Embodiments of the invention contemplate high efficiency emitters in solar cells and novel methods for forming the same. One embodiment of the improved emitter structure, called a high-low type emitter, optimizes the
solar cell performance by equally providing low
contact resistance to minimize ohmic losses and isolation of the
high surface recombination
metal-
semiconductor interface from the junction to maximize
cell voltage. Another embodiment, called an alternating
doping type emitter, provides regions of alternating
doping type for use with point contacts in the back-contact solar cells. One embodiment of the methods includes depositing and patterning a doped or undoped
dielectric layer on a surface of a substrate, implanting a fast-diffusing
dopant and / or a slow-diffusing
dopant into the substrate either simultaneously or sequentially, and annealing the substrate to drive in the dopants. Another embodiment of the methods includes using a physical
mask to form a patterned
dopant distribution in a substrate.