High-Efficiency n-Type PERT and PERL Solar Cells

n-type PERT and PERL structures both offer a high efficiency potential. In this work we applied ion implantation for the realization of both the emitter and the BSF of high-efficiency PERT and PERL structures and laser processes for local BSF formation showing efficiency benchmarks for those in principle industrially feasible technologies. For a fully ion implanted PERT solar cell we reached efficiencies up to 22.7%, showing that even at this high level no residual implantation damage is left and the Voc is limited by the profiles themselves. For the PERL structure we applied the PassDop process using two different passivation layer systems (based on SiCx and SiNx). With this laser based process we were able to reach conversion efficiencies up to 23.2%, showing that the laser doping process is as efficient as a PERL rear side realized by photolithography. To prove the industrial feasibility of these high-efficiency solar cell concepts we applied Ni plating as front side emitter metallization on a PassDop solar cell featuring a boron implanted emitter. For this cell type we were able to reach an efficiency of 21.7% in a first prove of principle batch.