N-type bifacial cell using simplified ion doping system

We investigated a new high efficiency low cost bifacial cell based on n-type substrate using a new simplified inline ion doping system, the so called ion shower. We were able to successfully form the boron doping layer and control the sheet resistance of the doped layer by controlling the doping and annealing parameters. Furthermore, we fabricated a bifacial Passivated Emitter and Rear Totally diffused (PERT) cell using the ion shower doping system to form a boron emitter. At first, PV performances were relatively low and the bifaciality was higher than 1. This result suggested that the recombination on the P⁺ side was greater than on the N⁺ side. Therefore, we applied the Alignment Free-Selective Emitter (AF-SE) technique to our cell to reduce the recombination loss of the emitter. As a result, all parameters were improved, and especially the increase in Jsc on the P⁺ side was remarkable, with the bifaciality decreased to 0.987. This clearly shows the effectiveness of AF-SE. In conclusion, we confirmed the feasibility of newly proposed high efficiency low cost n-type bifacial cell fabrication process using an ion shower doping system.