Electron beam crystallized silicon solar cells on glass substrates

For solar cells on low cost glass substrates a thickness of 20 /spl mu/m of a poly silicon film is sufficient as light absorber. Efficient deposition rates for the absorber up to 300 nm/min are achieved by means of a PECVD process in a mixture of trichlorosilane and hydrogen. For in-situ p-doping boron trichloride is added. An adjacent thin graphite layer is realized in the same plasma reactor by the addition of acetylene to improve the wetting of the silicon melt. The active silicon film is melted and crystallized by a line shaped electron beam which crosses the substrate at high velocities of up to 10 cm/s. A metal nitride film covering a glass substrate is used as a supporting mechanical layer and diffusion barrier during the crystallization process as well as electrical backside contact and backsurface reflector.