Abstract: An antireflection coating and a top contact pattern comprised of a thin layer of cerium covered by a layer of silver are applied to the front surface of the basic thin solar cell structure of U.S. Pat. No. 4,338,481. The contact pattern contains platforms for bonding to similar metallized platforms formed on the underside of a top cover glass. The top cover glass also comprises underside peripheral metallization for bonding to a similar bottom cover glass. After bonding of the top cover glass to the solar cell by laser welding or thermocompression bonding, the epitaxial layer at the back of the cell is thinned to a thickness of about 2 microns. The rear surface of the solar cell is then antireflectively coated, contacted, and bonded to a similarly prepared bottom cover glass, the top and bottom cover glasses being bonded and sealed at their peripheries. The bottom cover glass may also be ground and silvered so as to form a diffusive back side reflector.

Abstract: The performance and ruggedness of very thin silicon back surface field (BSF) solar cells are improved by the formation of a relatively thick, epitaxially grown, highly doped layer at the back of the cell and the formation of an arsenic doped layer at the top of the cell within the phosphorous diffused front region.As a result of these modifications and the method used for fabricating the modified cell, highly effective barriers, which diminish mobile charge loss by recombination, are created at the front and back of the cell base. The cell, consisting of a high resistivity, high minority carrier lifetime, very thin base sandwiched between effective barriers, permits achievement of almost ideal performance and has improved radiation damage resistance.The ruggedness of the very thin base cell is due to the addition of the relatively thick epitaxial layer in back of the base.