Abstract: A method and apparatus for doping silicon spheres (48) with a solid phosphorous source (41, 42) is disclosed. Two solid sheets (41, 42) of solid phosphorous source are held in a chamber (32) and aligned substantially parallel to one another for holding the plurality of silicon spheres therebetween. The chamber (32) temperature is increased to vaporize the sheets (41 and 42) to evenly diffuse phosphorous vapor into the silicon spheres (48).

Abstract: A method and apparatus for forming silicon spheres (40) from irregular-shaped particles (38) for use in solar cells are disclosed. The apparatus (10) generally comprises a vertically aligned cylindrical chamber (12) having an abrasive lining (32) integrally formed therein. The abrasive lining (32) is preferably a silicon carbide material. A gas source (36) is tangentially injected into the chamber (12) to create an gas vortex inside the chamber (12). This vortex induces the repeated collision of the particles (38) against the abrasive lining (32) to eventually form the silicon spheres (40) and simultaneously sizing the silicon spheres (40).