Abstract: A method for passivating a surface of a semiconductor material includes forming a layer stack having an aluminum oxide layer and an outer coating on the surface of the semiconductor material. The aluminum oxide layer and the outer coating are respectively formed in vacuum processes in which a vacuum is present. The vacuum is maintained between the forming of the aluminum oxide layer and the forming of the outer coating. Hydrogen and oxygen are supplied after the forming of the aluminum oxide layer and before the forming of the outer coating. A semiconductor substrate is also provided.

Abstract: The invention relates to a solar cell with a base layer (12) having a first doping that, together with a front layer (14) having a second doping of opposite polarity, forms a boundary layer. The solar cell has at least one front contact (18) and at least one rear contact (32). A passivation layer (24) and a tunnel contact layer (26, 28) are placed between the base layer (12) and the rear contact (32).