NOVELTY - Forming an emitter for solar cell in crystalline silicon substrate involves depositing amorphous silicon layer having doping level over upper surface of crystalline silicon substrate; depositing second amorphous silicon layer having second doping level on amorphous silicon layer; and heating the substrate and both amorphous silicon layers to temperature to cause solid phase epitaxial crystallization of the amorphous silicon layers, such that the amorphous silicon layers, after heating, have the same grain structure and crystal orientation as the underlying crystalline silicon substrate.    USE - For forming an emitter for solar cell in crystalline silicon substrate (claimed).    ADVANTAGE - The method enables formation of an emitter layer with a desired dopant profile such that a region of high recombination is minimized while at the same time the rest of the emitter has a low dopant concentration, thus eliminates many of the pre-cleaning, post-cleaning, and etching steps present in the prior art while providing a high performance.    DETAILED DESCRIPTION - Forming an emitter for solar cell in crystalline silicon substrate involves depositing first amorphous silicon layer having first doping level over an upper surface of crystalline silicon substrate; depositing second amorphous silicon layer having second doping level on first amorphous silicon layer; and heating the crystalline silicon substrate and first and second amorphous silicon layers to temperature to cause solid phase epitaxial crystallization of the first and second amorphous silicon layers, such that first and second amorphous silicon layers, after heating, have the same grain structure and crystal orientation as the underlying crystalline silicon substrate. An INDEPENDENT CLAIM is included for system for heat treating substrate comprising a first processing chamber having a first processing region and precursor source assembly, where the precursor source assembly is configured to deliver silicon-containing gas and dopant-containing gas to upper surface of substrate disposed in the first processing region to sequentially form lightly doped and heavily doped amorphous silicon layers on the upper surface of the substrate; and substrate support having substrate supporting surface and heating element that is positioned adjacent to the substrate supporting surface, where the substrate supporting surface is adapted to support bottom surface of substrate, and the heating element is configured to heat the substrate to temperature that is sufficient to crystallize the doped amorphous silicon layers disposed on the upper surface of the substrate.