An Improved Process for Bifacial n-PERT Solar Cells Fabricated with Phosphorus Activation and Boron Diffusion in One-step High Temperature

The bifacial n-PERT(Passivated Emitter Rear Totally diffused)solar cells were fabricated using a simplified process in which the activation of ion-implanted phosphorus and boron diffusion were performed simultaneously in a high-temperature process.For further efficiency improvement,the rear side doping level was regulated by applying two different implantation doses and the chemical etching step of boron rich layer(BRL)was added,and their effects on cell performance were investigated.The solar cells average efficiency reaches 20.35%with a bifaciality factor of 90%by optimizing rear side doping level,which can be explained by the decrease of Auger recombination.And it is further enhanced to 20.74%by removing the front side BRL due to the improvement of surface passivation and bulk lifetime.The improved fabrication process possesses the advantages of low complexity and cost and high cell efficiency and bifaciality factor which could provide a promising way to the commercial production of bifacial n-PERT solar cells.