Achieving highly passivated p-type TOPCon structure with iVoc of 735mV and J0,s of 5–7fA/cm² by tubular PECVD technology

Boron (B)-doped polysilicon (poly-Si)-based p-type tunneling oxygen-passivated contact (TOPCon) structures have emerged as a pivotal technology for next-generation back-junction and back-contact solar cells. According to the industrialization needs of high-efficiency passivated contact solar cells, this study systematically investigates the impact of film architectures and processing parameters on the passivation performance of p-type TOPCon structures. Through advanced tubular PECVD technology implementation, we demonstrate effective suppression of interfacial defect state density and carrier recombination rates via three key optimizations: 1) oxide layer structural engineering, 2) plasma energy distribution modulation through tunneled silicon oxide (SiOx) pulse spacing adjustment, and 3) a multi-stage annealing protocol in tubular furnaces incorporating temperature gradient control and rapid thermal activation. The optimized p-type TOPCon structure exhibits industrial-scale production potential with exceptional passivation performance: achieving an implied open-circuit voltage (iVoc) of 735.0 mV and a single-sided saturation current density (J_0,s) of 5.9 fA/cm² (tested on n-type silicon substrates, thickness of 120 μm, resistivity of 1 Ω·cm). This work establishes a low-cost process solution with mass production potential for TOPCon technology advancement.