Step-by-Step Doping Method of Phosphorous for High-efficiency and Low-cost Crystalline Silicon Cell

摘要

The invention relates to the technical field of solar cell manufacturing, and to a high-efficiency low-cost step-by-step doping method of 5 phosphorus for a crystalline silicon cell. The method comprises a depletion-type phosphorus diffusion, a high-concentration shallow layer diffusion and back-etching. The low-temperature low-phosphorus deposition is performed on a p-type silicon substrate by controlling the oxygen flow rate, the nitrogen flow rate, and the phosphorus oxychloride 10 flow rate, and then the phosphorus in the phosphorosilicate glass is depleted by a long period of high-temperature drive-in to achieve a low surface concentration layer n+. A second deposition and drive-in are performed on the non-phosphorus glass to increase the surface concentration, and thus form a very thin high-concentration layer n++, 15 which can be quickly etched away by back-etching. The distribution of phosphorus dopant in different regions can be independently and precisely controlled, to ensure a low doping concentration and a low recombination current in a non-electrode region, thereby ensuring a high open-circuit voltage. An electrode region has a high doping concentration, and has a 20 good ohmic contact with a metal electrode, such that the fill factor is not compromised, thereby improving the photoelectric conversion performance of the cell on a whole.