24.4% industrial tunnel oxide passivated contact solar cells with ozone-gas oxidation Nano SiOx and tube PECVD prepared in-situ doped polysilicon

Ozone-gas oxidation (OGO) technology, capable of integrating into tube plasma-enhanced chemical vapor deposition (PECVD) technology, is developed to prepare the Nano SiOx layer for tunnel oxide passivated contact (TOPCon) solar cells in this work. The effects of gas flow, oxidation temperature, and annealing temperature on passivation quality are investigated. The X-ray photoelectron spectroscopy (XPS) indicates that OGO SiOx possesses a Si4+ proportion of about 20%, higher than the nitric acid oxidized (NAOS) SiOx and plasma-assisted N2O oxidation (PANO) SiOx. The implied open-circuit voltage (iVoc) of the hydrogenated lifetime sample is promoted to more than 740 mV with the highest value of 748 mV, corresponding to a lowest single-sided saturation current density (J0,s) of 3.1 fA/cm2. The contact resistivity extracted from the Cox-Strack method is < 9 mΩ cm2 as the annealing temperature is more than 840 °C. Finally, we prepared the large-sized TOPCon solar cells with an average efficiency of 24.37% and a maximum efficiency of 24.41%, respectively. The above work shows that the tube PECVD technology integrated with ozone gas oxidation has the potential for the mass-production TOPCon industry.