US Patent 7846762 Integrated emitter formation and passivation

Embodiments of the present invention provide a method for forming an emitter region in a crystalline silicon substrate and passivating the surface thereof by depositing a doped amorphous silicon layer onto the crystalline silicon substrate and thermally annealing the crystalline silicon substrate while oxidizing the surface thereof. In one embodiment, the deposited film is completely converted to oxide. In another embodiment, the doped amorphous silicon layer deposited onto the crystalline silicon substrate is converted into crystalline silicon having the same grain structure and crystal orientation as the underlying crystalline silicon substrate upon which the amorphous silicon was initially deposited during emitter formation. In one embodiment, at least a portion of the converted crystalline silicon is further converted into silicon dioxide during the emitter surface passivation.