This invention focuses on enhancing the performance of silicon solar cells by improving the quality of silicon nitride films used as anti-reflective coatings and passivation layers. Traditional Plasma-enhanced chemical vapor deposition (PECVD) silicon nitride films often have defects like pinholes, which can cause issues during further processing. The proposed method involves post-deposition plasma treatments using argon (Ar), nitrous oxide (N2O), or a combination of both. These treatments increase the film's density, reduce defects, and improve the interface quality between silicon and silicon nitride. As a result, the minority carrier lifetime in silicon is significantly enhanced, leading to better solar cell efficiency and stability even at high temperatures.
Figure (1) Graphical representation of minority carrier lifetime observed after post treatment of passivation layer; (2) Graphical representation of decrement in interface state density after post treatment
Silicon nitride films used in silicon solar cells often suffer from low density and pinholes, leading to defects during further processing like electroplating. These defects degrade the interface quality between silicon and silicon nitride, reducing the efficiency and stability of solar cells. There is a need for a method to enhance the film quality and interface properties to improve the overall performance of silicon solar cells.
- Post-deposition plasma treatment using Ar, N2O, or Ar+N2O: This method enhances the density of Plasma-enhanced chemical vapor deposition (PECVD) silicon nitride films, which reduces pinholes and minimizes defects during further processing, leading to more reliable solar cell performance.
- Significant reduction in interface state density: Achieved through specific plasma treatments, this reduction improves the electrical properties at the silicon-silicon nitride interface, resulting in better efficiency and performance of solar cells.
- Enhanced minority carrier lifetime: Plasma treatments significantly increase the minority carrier lifetime, contributing to higher efficiency and longer operational life of silicon solar cells.
- Improved surface passivation: The treatments improve the passivation of the silicon emitter surface, which enhances the overall effectiveness of the anti-reflective coating and boosts solar cell efficiency.
- Stability at high temperatures: The enhanced passivation remains stable up to 450°C, ensuring that solar cells maintain their performance and durability in various environmental conditions.
- Reduction in background plating: Using oxidizing species treatment reduces unwanted background plating, which prevents defects and ensures the integrity of the silicon wafer during metallization processes.
- Versatility of plasma treatments: The ability to use Ar, N2O, or a combination of both provides flexibility in the treatment process, allowing for tailored improvements in film density and interface quality, adaptable to different manufacturing needs.
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- Increased solar cell efficiency: Higher efficiency in solar cells leads to more effective harnessing of solar energy, contributing to greater adoption of renewable energy sources.
- Enhanced longevity of solar cells: Longer-lasting solar cells reduce the frequency of replacements, lowering electronic waste and environmental impact.
- Cost-effective energy solutions: Improved performance and stability of solar cells make solar energy more cost-competitive, increasing accessibility for a broader population.
- Reduction in fossil fuel dependence: Higher efficiency and reliability of solar cells encourage the shift from fossil fuels to sustainable energy, decreasing greenhouse gas emissions.
- Promotion of green technology: Advances in solar cell technology foster innovation in green technologies, supporting environmental sustainability initiatives.
Silicon solar cells, renewable energy, electronic waste reduction, green technology, CMOS technology, semiconductor manufacturing, metallization processes, energy independence
636/MUM/2015
404618