Self-aligning, industrially feasible back contacted silicon solar cells with efficiencies >18%

New concepts of high-efficiency solar cells obtained by a simple cost-effective manufacturing process are required for a drastic reduction of the cost of solar electricity. In this paper experimental results for a novel back contacted silicon solar cell, the Back-OECO cell, are presented. The concept exclusively includes industrially feasible, mask- and aligning-free processing steps and has the potential for very high efficiencies. Low-cost fabrication steps are consisting of rear side grooving, the self-aligning OECO (Oblique Evaporation of COntacts) technology and a low temperature (/spl les/400/spl deg/C), high quality silicon nitride passivation. Taking advantage of the OECO technology, contact separation on the rear side is achieved extremely simple and reliable. Because of the special design with a grooved rear side the cell has the inherent advantage of being bifacially sensitive. Cell efficiencies of 18.1% and 17.4% for front and rear side illumination, respectively, were achieved.