Principle
Based on the existing passivatedemitter rear contact (PERC) cell technology, the laser boron doping technology deposits or prints the boron doping source to form laser heavily doped region P++ layer in the process of laser back grooving. The P++ layer formed by laser doping can effectively reduce the back-contact recombination rate and the back silicon-aluminum contact resistance, increase the solar cell open-circuit voltage (Voc) and fill factor (FF), and improve the cell conversion efficiency.
Process Introduction
Laser boron doping is one of the directions for future upgrade of PERC cell technology. It uses CVD deposition or printing to form a layer of boron doping source on the back of PERC blue tape. Through the thermal effect generated in the laser grooving process, boron element is doped into the silicon substrate synchronously to form the P++ layer, that is, the heavily doped region. For one thing, the heavily doped region forms the P++P high-low junction to generate a field passivation effect; for another, it can effectively reduce the aluminum-silicon contact resistance, and increase Voc and FF, thus improving the solar cell conversion efficiency.
