Solar Cell Edge Region Layout for Silicon Glass Over-Etching
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Solution Overview
Problem
The current process of forming semiconductor layers in solar cells using LPCVD leads to issues such as incomplete removal and over-etching of the silicon glass layer, resulting in surface defects and reduced photoelectric conversion efficiency.
Innovation Solution
The solar cell design includes a substrate divided into an edge region and a center region, with the edge region flush or lower than the center region, and a passivation layer covering the edge region to prevent over-etching, reducing surface defects and improving electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LPCVD is used to prepare the polycrystalline silicon layer, then the conductivity of majority carriers is improved, but over-etching occurs in the silicon glass layer removal process
Solution Approach 1:
The patent applies local quality by making the edge region flush with or lower than the center region, creating a height difference that provides selective protection during etching. The passivation layer is selectively formed on the edge region with a thickness of 50-200 nm, providing localized protection against over-etching while maintaining the LPCVD process benefits for the center region's polycrystalline silicon layer conductivity.
2Ease of manufacture
If the edge region is not protected, then the manufacturing process is simpler, but electrical recombination and leakage occur at the cell edge
Solution Approach 1:
The patent segments the substrate into two distinct regions: a center region and an edge region, with different structural characteristics. The edge region is made flush with or lower than the center region, and a passivation layer is selectively applied to the edge region. This segmentation allows different processing and protection strategies for different areas, preventing edge recombination and leakage while maintaining overall manufacturing efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design reduces electrical recombination and leakage at the cell edge, enhancing open circuit voltage and short circuit current, thereby improving photoelectric conversion efficiency.
Implementation Method 1
The solar cell generates carriers by using the photovoltaic effect principle and introduces the carriers out by using an electrode
Implementation Method 2
Chemical passivation of the tunneling oxide layer and field passivation of the polycrystalline silicon layer can significantly reduce a recombination rate of minority carriers on the silicon surface
Implementation Method 3
the highly-doped polycrystalline silicon layer can significantly improve the conductivity of majority carriers
Data Source
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AI summary
Provided are a solar cell, a method for preparing a solar cell, and a photovoltaic module, relating to the field of photovoltaics. The solar cell includes a substrate, a dielectric layer and a doped semiconductor layer which are stacked, a passivation layer, and electrodes. The substrate has a first surface. The first surface includes an edge region and a center region. The edge region surrounds the center region. The edge region is substantially flush with or closer to the second surface than the center region. The dielectric layer is formed over the center region. The passivation layer covers the edge region and a surface of the doped semiconductor layer facing away the dielectric layer. The electrodes are located in the center region, and penetrate the passivation layer in a thickness direction to be in electrical contact with the doped semiconductor layer.