A SOLAR CELL AND FABRICATION METHOD USING CRYSTALLINE SILICON BASED ON LOWER GRADE FEEDSTOCK MATERIALS

• Main Authors: RAKOTONIAINA JEAN PATRICE, BLOSSE ALAIN, KIRSCHT FRITZ, KAES MARTIN, OUNADJELA KAMEL, ZERGA ABDELLATIF, HEUER MATTHIAS, ZICKERMANN DIRK
• Format: Patent
• Language: English; Korean
• Published: 21.12.2010
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

Formation of a solar cell device from upgraded metallurgical grade silicon which has received at least one defect engineering process and including a low contact resistance electrical path. An anti-reflective coating is formed on an emitter layer and back contacts are formed on a back surface of the bulk silicon substrate. This photovoltaic device may be fired to form a back surface field at a temperature sufficiently low to avoid reversal of previous defect engineering processes. The process further forms openings in the anti-reflective coating and a low contact resistance metal layer, such as nickel layer, over the openings in the anti-reflective coating. The process may anneal the low contact resistance metal layer to form n-doped portion and complete an electrically conduct path to the n-doped layer. This low temperature metallization (e.g., <700° C.) supports the use of UMG silicon for the solar device formation without the risk of reversing earlier defect engineering processes.