Chemical vapor deposition (CVD) plays a crucial role in the fabrication of crystalline silicon (c-Si) solar cells. The structures, morphologies and properties of the silicon oxide ( \(\text {SiO}_x\) ) passivated contacts vary significantly with the specific CVD technique employed, including atmospheric-pressure (APCVD), low-pressure (LPCVD), and plasma-enhanced (PECVD) methods. This study demonstrates that, although APCVD offers the advantages of low cost and high deposition rate, the random motion of carrier gas molecules results in the non-uniform \(\text {SiO}_x\) films with a high defect density. As a result, the TOPCon solar cells passivated with APCVD-SiO? exhibit the lowest open-circuit voltage (735.9 mV) and power conversion efficiency (24.9%). In contrast, the \(\text {SiO}_x\) layers produced by LPCVD and PECVD are dense and uniform, providing superior surface passivation. The average open-circuit voltages of the LPCVD- \(\text {SiO}_x\) and PECVD- \(\text {SiO}_x\) passivated TOPCon solar cells reach 743.9 mV and 743.8 mV, respectively. Ultimately, the plasma-enhanced chemical activation of the reactant gases enables the PECVD-passivated TOPCon solar cells to achieve the highest short-circuit current density (41.43 \(\text {mA}\cdot \text {cm}^{-2}\) ) and an overall power conversion efficiency of 25.8%.
