Patent attributes
A method utilizing spatially selective laser doping for irradiating predetermined portions of a substrate of a semiconductor material is disclosed. Dopants are deposited onto the surface of a substrate. A pulsed, visible beam is directed to and preferentially absorbed by the substrate only in those regions requiring doping. Spatial modes of the incoherent beam are overlapped and averaged, providing uniform irradiation requiring fewer laser shots. The beam is then focused to the predetermined locations of the substrate for implantation or activation of the dopants. The method provides for scanning and focusing of the beam across the substrate surface, and irradiation of multiple locations using a plurality of beams. The spatial selectivity, combined with visible laser wavelengths, provides greater efficiency in doping only desired substrate regions, while reducing the amount of irradiation required. Savings in cost and manufacturing throughput can be achieved, particularly with respect to doping poly-crystalline silicon.
