Solar Cells, 15 (1985) 239 - 245 239 INCOHERENT-LIGHT INDUCED DIFFUSION OF PHOSPHORUS AS A DOPING PROCEDURE FOR LOW-COST SILICON SOLAR CELLS A. NYLANDSTED LARSEN Institute of Physics, University of ~arhus, DK-8000 ~arhus (Denmark) L. DRUD NIELSEN* Physics Laboratory III, Technical University of Denmark, DK-2800 Lyngby (Denmark) (Received March 4, 1985; accepted May 1, 1985) Summary •Diffusion of phosphorus into p-type silicon from spun-on phosphoro- silica films has been induced by means of incoherent light from a xenon arc- lamp. A suitable process for solar cell preparation appears to be heating for 20 s to 1000 °C, followed by gradual cooling. Sheet resistivities of around 35 ~2/[] may be achieved under these conditions, with no appreciable degradation of the bulk-material properties. Doping profiles measured by the Hall effect exhibit a maximum concentration of 2 - 3 X 1020 cm -3 at the silicon surface and a junction depth of about 1500 A. A number of test-cell batches have been prepared from single- as well as polycrystalline material, and very favourable and reproducible spectral-response characteristics have been found. In spite of the non-optimized cell design and a rather primitive antireflective coating, AM 1 efficiencies of up to 12.7% (single-crystal cell) and 8.2% (polycrystalline cell) have been recorded. 1. Introduction The need to cut down the manufacturing costs of silicon solar cells has led to extensive studies of new doping procedures that are also suited to the preparation of p/n ,junctions in polycrystalline materials. Various beam processing techniques [1] have attracted considerable interest, either for annealing damaged layers after ion implantation or as means of inducing diffusion of dopants from deposited surface layers. We have found the latter approach particularly interesting as it allows p/n junction formation without vacuum or special-gas processes and in *Present address: Institute of Circuit Theory and Telecommunication, Technical University of Denmark, DK-2800 Lyngby, Denmark. 0379-6787/85/$3.30 © Elsevier Sequoia/Printed in The Netherlands