NOVELTY - A solar cell contains substrate (200), polycrystalline-silicon thin-film layer (212), contact under-layer (206), metal layer (204), n-type doped amorphous-silicon thin-film layer (214), optional intrinsic layer, transparent conductive layer (216) and front-side electrode (218). The polycrystalline-silicon thin-film layer contains layer (p+) provided on substrate, and is hydrogenated. The contact under-layer is provided between substrate and polycrystalline-silicon thin-film layer. The metal layer is provided below contact layer.    USE - Solar cell e.g. silicon heterojunction solar cell.    ADVANTAGE - The solar cell is economical and non-toxic, and has stability for long period of time.    DETAILED DESCRIPTION - A solar cell contains substrate, polycrystalline-silicon thin-film layer, contact under-layer, metal layer, n-type doped amorphous-silicon thin-film layer, optional intrinsic layer, transparent conductive layer and front-side electrode. The polycrystalline-silicon thin-film layer contains layer (p+) provided on substrate, and is hydrogenated. The contact under-layer is provided between substrate and polycrystalline-silicon thin-film layer. The metal layer is provided below contact layer, in which a portion of metal layer reaches layer (p+) through contact under-layer. The n-type doped amorphous-silicon thin-film layer is provided on polycrystalline silicon thin-film layer forming heterojunction. The optional intrinsic layer is provided between polycrystalline-silicon thin-film layer and n-type doped amorphous-silicon thin-film layer. The transparent conductive layer is provided on n-type doped amorphous-silicon thin-film layer. The front-side electrode situated is provided on transparent conductive layer. An INDEPENDENT CLAIM is included for fabrication of solar cell.    DESCRIPTION OF DRAWING(S) - The drawings show schematic view of manufacture of solar cell.    Substrate (200)    Metal layer (204)    Contact under-layer (206)    Polycrystalline-silicon thin-film layer (212)    N-type doped amorphous-silicon thin-film layer (214)    Transparent conductive layer (216)    Front-side electrode (218)