Excellent surface passivation of p-type TOPCon enabled by ozone-gas oxidation with a single-sided saturation current density of ∼ 4.5 fA/cm2

• Published in: Solar energy 2023-07, Vol.259, p.348-355
• Main Authors: Lin, Na, Yang, Zhenhai, Du, Haojiang, Ding, Zetao, Liu, Zunke, Xing, Haiyang, Xiao, Mingjing, Ou, Yali, Liu, Wei, Liao, Mingdun, Yan, Baojie, Huang, Shihua, Zeng, Yuheng, Ye, Jichun
• Format: Article
• Language: English
• Subjects: Boron-doped polysilicon; Ozone gas (O3) oxidation; p-Type TOPCon; Passivation quality; PECVD
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2023.05.028

•The double-sided p-TOPCon passivated lifetime samples with p-type Si substrates achieve a high implied open-circuit voltage of ∼ 734 mV and a low single-sided saturation current density of ∼ 4.5 fA/cm2.•The contact resistivity is below 5 mΩ‧cm2, yielding a remarkable selectivity of 15.6.•The precursor cell manifests an excellent iVoc of 717 mV.•The proof-of-concept p-TOPCon solar cells exhibit a remarkable efficiency of 22.23%. High-quality p-type tunnel oxide passivated contact (p-type TOPCon) is a feasible technical solution to further improve the efficiency of TOPCon silicon solar cells. Plasma-enhanced chemical vapor deposition (PECVD) technology route could deposit boron-doped amorphous silicon film in-situ and thus becomes one of the most promising industry routes to prepare the TOPCon structure. However, the passivation quality of p-type TOPCon by PECVD is not satisfactory till now. In this work, we develop the high-performance p-type TOPCon technology by integrating the ozone-gas oxidation to prepare the ultra-thin SiOx film, which shows excellent passivation and contact properties. The experimental results suggest that the double-sided p-type TOPCon passivated samples with p-type Si substrates receive a maximal implied open-circuit voltage (iVoc) of ∼ 734 mV together with a minimum single-sided saturation current density (J0,s) of ∼ 4.5 fA/cm2. Correspondingly, the contact resistivity is less than 5 mΩ·cm2, yielding a high selectivity S10 of 15.6, which is one of the best values for p-type TOPCon technology. As a result, the precursor cell manifests an excellent iVoc of 717 mV, and the p-type silicon solar cell with rear-sided p-type TOPCon passivating contact receives a high efficiency of 22.23%. Generally, this work provides a promising technology for preparing the high-quality p-type TOPCon passivating contact for industrial application.