24.7% industrial tunnel oxide passivated contact solar cells prepared through tube PECVD integrating with plasma-assisted oxygen oxidation and in-situ doped polysilicon

Tunnel oxide passivated contact (TOPCon) solar cells have gradually dominated the industrial silicon solar cells. In this paper, we have adopted the tube plasma-enhanced chemical vapor deposition (PECVD) technology integrating with nano SiOx (Tox) and in-situ phosphorus-doped polysilicon (n + poly-Si), in which Tox is prepared by plasma-assisted oxygen (O2) oxidation. Passivation and contact performance of TOPCon solar cells have been investigated under different thicknesses of Tox, and the following simulation has confirmed the optimal electrical properties, i.e., the implied open-circuit voltage (iVOC) of the hydrogenated lifetime sample is promoted to more than 736.1 mV on the textured wafer, corresponding to a lowest single-sided saturation current density (J0) of 4.6 fA/cm2, and the contact resistivity of 1.55 mΩ cm2 extracted from the transmission line method. Characterizations are carried out to conform the rear stack passivation layers satisfy the requirement of the high-efficiency TOPCon solar cells. Finally, we have fabricated the large-sized TOPCon solar cells with an average efficiency of 24.5% and a maximum efficiency of 24.7%, respectively. The above work has demonstrated the tube PECVD technology integrating with plasma-assisted O2 oxidation and in-situ doped poly-Si has the potential for the mass-production TOPCon in industry.