Patent ID: 8241945

Claim:
A method comprising: providing a substrate comprising a semiconductor wafer having a front surface and a back surface and having at least one dielectric layer formed on the front surface of the semiconductor wafer, wherein the semiconductor wafer is initially doped with a first type of charge carrier and comprises a p-n junction formed through doping the front surface of the semiconductor wafer with a second type of charge carrier, the second type of charge carrier being opposite to the first type of charge carrier; forming a via through the at least one dielectric layer by using a laser to ablate a region of the at least one dielectric layer such that a portion of the front surface of the semiconductor wafer is exposed by the via; applying a self-doping metal paste to a portion of the substrate such that the applied self-doping metal paste is applied to the via, wherein the self-doping metal paste comprises a dopant comprising the second type of charge carrier; and heating the substrate and self-doping metal paste to drive at least some dopant from the self-doping metal paste into the portion of the front surface of the semiconductor wafer exposed by the via to form a selective emitter region and to form a contact overlying the selective emitter region, the contact being in electrical contact with the p-n junction at the via location, wherein the selective emitter region has a higher doping concentration of the second type of charge carrier than a region of the front surface of the semiconductor wafer adjacent to the selective emitter region.