Low temperature rear surface metallization of multi-crystalline silicon solar cells for improved bulk lifetime

Multi-crystalline silicon PERC cells with Al-alloyed rear point contacts are limited in efficiency potential by light induced degradation, which is activated by high temperature firing of metallization pastes. Replacement of this rear surface design with a low temperature metallization technology will mitigate this degradation process and facilitate thermal processes that improve efficiency, such as extended gettering. Point-contacting by localized dielectric breakdown is a low temperature process to contact the rear surface of PERC style cell structures, here it has been applied to multicrystalline silicon for the first time. The implied open circuit voltage is preserved after contact formation successfully, demonstrating the separation of high temperature firing from metallization.