Boron Implanted Junction with In Situ Oxide Passivation and Application to p-PERT Bifacial Silicon Solar Cell

摘要

Boron junction and its passivation is an active topic in photovoltaic research due to its importance to passivated emitter and rear totallydiffused (PERT) bifacial Si solar cell. In this paper, a systematic study on boronimplanted junction, its passivation and ohmic contact formation, as well as application to pPERT bifacial cells has been presented. More specifically, the impact of junction profile and surface passivation on boron junction quality, which can be influenced by implantation and in situ oxidation anneal parameters is studied. Goodquality boron emitter and metal/p+Si ohmic contact are achieved, as demonstrated by emitter saturation current of 530fAcm2 and specific contact resistance of 36mcm1. A roadmap for a pPERT bifacial cell using fully ion implanted (boron and phosphorus) technology, based on which pPERT bifacial cells demonstrats front side efficiency of 20.6% (open circuit voltage of 658mV), rear side efficiency of 17% and bifaciality factor of 0.820.87 is also presented. Effective cell efficiency of 22% is achieved with a Halm IVtester with white transporting belts that enhance reflection about 10% from the cell rear.