NOVELTY - The method for producing a solar cell from an n-doped silicon semiconductor substrate and a p-doped silicon semiconductor substrate, which have a first main surface that serves as light incidence side when used and a second main surface that serves as back side, comprises forming a n+ region, a front surface field and an n+ emitter region in the first main surface, and forming a p+ emitter and a p+ region i.e. a back surface field in the second main surface by doping with aluminum, where the doping with aluminum is carried out by the diffusion of the aluminum.    USE - Method for producing a solar cell e.g. an interdigitated back contact solar cell from an n-doped silicon semiconductor substrate and a p-doped silicon semiconductor substrate.    ADVANTAGE - The method is capable of simply and economically producing the solar cell with high quality, high lifespan and high light intensity.    DETAILED DESCRIPTION - The method for producing a solar cell from an n-doped silicon semiconductor substrate and a p-doped silicon semiconductor substrate, which have a first main surface that serves as light incidence side when used and a second main surface that serves as back side, comprises forming a n+ region, a front surface field and an n+ emitter region in the first main surface, and forming a p+ emitter and a p+ region i.e. a back surface field in the second main surface by doping with aluminum, where the doping with aluminum is carried out by the diffusion of the aluminum from an aluminum-containing source layer applied to the second main surface, so that the aluminum concentration profile has a profile in the semiconductor substrate starting from the second main surface towards the semiconductor substrate, where the highest aluminum concentration is present on the second main surface or directly next to it. A dielectric passivation layer and/or an anti-reflective layer are deposited in the first main surface and are formed by screen printing, ink-jet printing or aerosol printing. A finger-like contact structure is formed with subsequent chemical or galvanic reinforcement to a solar cell front side. The n+ region and n+ emitter region is formed by diffusion of phosphorus from a precursor layer or a phosphorus oxychloride-gas phase. The source layer or a sequence of source layers is produced by optionally sequentially executed evaporation or sputtering without intervening interruption of the vacuum- and/or gas phase atmosphere. A surface layer of the source layer or last source layer is produced in same vacuum- and/or gas phase process like the source layer without interruption of the vacuum- and/or gas phase atmosphere. The second main surface is covered with a thin metal layer in a further vacuum- and/or gas phase deposition process. The aluminum-containing source layer and optionally present cover layer or cover layer sequence are etched off after the thin metal layer. The dielectric passivation layer is deposited before the deposition of the thin metal layer and is locally provided with openings before the deposition of the metal layer. The second main surface is locally contacted through the openings during subsequent deposition of the metal layer. The n+ doping of the first main surface is carried out in a cooling phase of the steps of the p+ doping of the second main surface. An INDEPENDENT CLAIM is included for a solar cell.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic representation of a method for producing a solar cell.