Method of manufacturing solar cells

A method of manufacturing a solar cell comprising a semiconductor wafer having a region of a first conductivity type with a first major surface on its front radiation-incident side and a second major surface on its rear side, a first surface layer of a second conductivity type opposite to that of the first which adjoins said first major surface and forms with said region the active p-n junction of said solar cell, and a second surface layer of said first conductivity type which adjoins said second major surface and has a higher doping concentration than that of said region, which comprises:

• providing a first glassy layer comprising a first dopant determinative of the first conductivity type on said second major surface and spaced apart from the edges of said semiconductor wafer;
• then
• providing a second undoped glassy layer on said first glassy layer and on the edge portions of said second major surface and the edges of said semiconductor wafer not covered by said first glassy layer;
• and then
• heating said semiconductor wafer while introducing a second dopant determinative of said second conductivity type into said first major surface, said second undoped glassy layer preventing the doping of said second major surface and said edges by said second dopant, while that portion of said second major surface beneath said first glassy layer is doped by said first dopant from said first glassy layer.