PERC Solar Cells on p-Type Cz-Si Utilizing Phosphorus-Doped SiNX Layers

We apply phosphorus-doped silicon nitride (SiNX:P) layers on the front surface of p-type Czochralski-grown silicon (Cz-Si) passivated emitter and rear cells (PERC). The layers are formed using industrial-type plasma-enhanced chemical vapor deposition. They provide excellent surface passivation with implied open-circuit voltages text{i}V{text{OC}} up to 695 mV and similar optical properties as conventional undoped SiNX anti-reflection layers with text{i}V{text{OC}} peaking at 685 mV. The emitter dark saturation current density at the passivated textured surface is j{rm 0e} â 40 fA/cm² for a lowly-doped emitter with sheet resistance R{text{sh}} â 160 Ω/sq. For realizing laser-doped selective emitters (LDSE), local laser processing is applied to introduce additional dopants from the SiNX:P layer into the silicon. Thereby, highly doped areas are formed in which R{text{sh}} is decreased down to 55 Ω/sq. We refer to this as the nPassDop approach, which provides both lo cal high doping and local structuring of the anti-reflection coating in a single process step. Low contact resistivity of around 1.5 mΩcm2 is measured for screen-printed and fired silver contacts on the locally laser-doped areas. A first proof of concept of large-area p-type Cz-Si PERC solar cells with front side text{SiN}{text{X}}text{:P} passivation and LDSE structure yield energy conversion efficiencies up to 20.9%.