The invention relates to a method for producing a solar cell from a silicon substrate, which has a first main surface serving as a light incidence side during use and a second main surface serving as a rear side, having a passivation layer on the second main surface, comprising the steps of: applying an oxide-containing layer to the second main surface of the silicon substrate; and heating the silicon substrate to a temperature of at least 800°C to compact the oxide-containing layer and to oxidize the interface between the oxide-containing layer and the second main surface of the silicon substrate to form a thermal oxide, wherein an oxygen source delivers oxygen for the oxidation.