and 4 b these solder pads are metallic surfaces advantageously approximately circular that simplify due to their material properties the electrically conductive connection of the connection structures 4 a and 4 b to a cell connector via the solder pads fig5 shows a section perpendicular to the plane of the drawing along the line a shown with dashed lines in fig1 the semiconductor substrate 1 is covered on the front side essentially over the entire surface by the emitter 2 a up to the holes in the semiconductor substrate 1 that are filled by the via metallization areas 7 above the via metallization 7 a metallization finger of the front side n type contact structure 3 a is shown in longitudinal section on the back side of the semiconductor substrate 1 the back side n type contact structure 3 b is arranged in the region in which the via metallization 7 meets the back side back side n type contact structure 3 b via metallization 7 and front side n type contact structure 3 a border directly on each other and are connected in an electrically conductive way the emitter 2 a extends on the hole walls along the via metallization 7 toward the back side of the semiconductor substrate 1 and covers the back side in a region that is slightly larger than the region covered by the back side n type contact structure 3 b those regions of the semiconductor substrate 1 that are not n doped i e that are not constructed as emitter 2 a represent p doped regions and thus form the base 2 b.