Patent ID: 8110431

Claim:
A method for manufacturing a selective emitter solar cell comprising: providing a substrate comprising a p-type base layer; introducing dopant to at least a first region of the front surface of the p-type base layer by ion implantation; introducing dopant to at least a second region of the front surface of the p-type base layer by ion implantation, wherein the second region is more heavily doped than the first region, and wherein the dopant introduced to the first and second regions is of n-type conductivity; annealing the substrate, wherein annealing comprises heating the substrate in a furnace to a temperature to: anneal the implant damage; activate dopant from the first and second regions; and drive the dopant from the first and second regions deeper into the substrate, thereby forming a selective emitter layer on the front surface of the p-type base layer; introducing oxygen into the furnace during the annealing step to: form a passivating oxide layer on at least the front surface of the selective emitter layer; depositing an amorphous silicon nitride layer on the front surface of the passivating oxide layer thereby forming an antireflection layer; screen-printing one or more front contacts on the amorphous silicon nitride layer in alignment with the second region of the front surface of the p-type base layer; screen-printing one or more aluminum back contacts on the back surface of the p-type base layer; co-firing the one or more front and back contacts to provide electrical connections to the solar cell; and forming an aluminum-doped p + silicon layer by liquid phase epitaxial regrowth at the interface of the back surface of the p-type base layer and the back contacts during the co-firing of the front and back contacts, wherein the back contacts provide an electrical connection to the aluminum-doped p + silicon layer.