n-Type polysilicon passivating contact for industrial bifacial n-type solar cells

We present a high-performance bifacial n-type solar cell with LPCVD n(+) polysilicon (polySi) back side passivating contacts and fire-through screen-printed metallization, processed on full area 6 '' Cz wafers. The cells were manufactured with low-cost industrial process steps yielding a best efficiency of 20.7%, and an average V-oc of 674 mV. We analysed effects of variation of doping level, thickness, and oxide properties of the n-type polySi/SiOx layers, as well as hydrogenation from a PECVD SiNx:H coating, which led to recombination current densities down to similar to 2 fA/cm(2) and similar to 4 fA/cm(2) on planar and textured surface, respectively. Analysis shows that the wafer bulk lifetime in the cell is high and that the V-oc of the cell is limited by the J(o) of the uniform diffused boron emitter and its contacts. Ways to improve the efficiency of the cell to > 22% are indicated. (C) 2016 Elsevier B.V. All rights reserved.