Electronic Quality Enhancement of Multicrystalline Silicon via SiNx and H2 Plasma Passivation Using Plasma-Enhanced Chemical Vapor Deposition for Photovoltaic Applications

This study explored advancements in photovoltaic technologies by enhancing the electronic quality of multicrystalline silicon (mc-Si) through silicon nitride (SiNx) and hydrogen (H2) plasma deposition via plasma-enhanced chemical vapor deposition (PECVD). This innovative approach replaced toxic chemical wet processes with H2 plasma and SiNx. The key parameters of silicon solar cells, including the effective lifetime (τeff), diffusion length (Ldiff), and iron concentration ([Fe]), were analyzed before and after this sustainable solution. The results show significant improvements, particularly in the edge region, which initially exhibited a low τeff and a high iron concentration. After the treatment, the τeff and Ldiff increased to 7 μs and 210 μm, respectively, compared to 2 μs and 70 μm for the untreated mc-Si. Additionally, the [Fe] decreased significantly after the process, dropping from 60 ppt to 10 ppt in most regions. Furthermore, the treatment led to a significant decrease in reflectivity, from 25% to 8% at a wavelength of 500 nm. These findings highlight the effectiveness of the PECVD-SiNx and H2 plasma treatments for improving the optoelectronic performance of mc-Si, making them promising options for high-efficiency photovoltaic devices.