N-Type Silicon Composition Control for Low-Defect Solar Substrates
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Solution Overview
Problem
Existing technologies face challenges in improving the quality of n-type silicon blocks and substrates, which are crucial for enhancing the efficiency of solar cells, particularly when compared to polycrystalline silicon substrates.
Innovation Solution
A manufacturing process involving mono-like casting is employed to create n-type silicon blocks and substrates, utilizing a donor and acceptor elements, carbon, and oxygen, with a higher segregation coefficient for the donor, to achieve a pseudo-monocrystalline structure with reduced defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mono-like casting is used to manufacture n-type silicon blocks, then the production efficiency is improved compared to traditional methods, but the quality and electrical properties of the silicon blocks deteriorate due to higher defect rates and lower purity
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentration ratios of donors to acceptors and carbon to oxygen in the silicon melt during mono-like casting. By optimizing these compositional parameters, the process achieves both high production efficiency and improved silicon block quality with reduced defects and enhanced electrical properties.
Solution Approach 2:
The patent implements local quality by creating specific compositional zones within the silicon block during solidification. The controlled segregation of dopants and impurities results in optimized local regions with appropriate electrical properties, improving overall block quality while maintaining efficient production.
2Ease of manufacture
If conventional doping methods are used in n-type silicon blocks, then the manufacturing process is simple, but the electrical properties and conversion efficiency deteriorate due to insufficient control over dopant distribution
Solution Approach 1:
The patent changes the doping parameters by specifying precise concentration ratios of donors to acceptors (1:0.01 to 1:10) and controlling carbon to oxygen ratios. This parameter optimization improves electrical properties and conversion efficiency while maintaining manufacturing simplicity through a single-casting process that inherently achieves uniform dopant distribution.
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
The process results in higher-quality n-type silicon blocks and substrates with improved electrical properties, potentially leading to enhanced conversion efficiency in solar cells.
Implementation Method 1
The donor has a greater segregation coefficient in silicon than the acceptor
Data Source
AI summary
An n-type silicon block contains a donor including a group 15 element, an acceptor including a group 13 element, carbon, and oxygen. The n-type silicon block includes a first portion including more carbon atoms than oxygen atoms per unit volume. The n-type silicon block includes more atoms of the donor than atoms of the acceptor per unit volume. The donor has a greater segregation coefficient in silicon than the acceptor. An n-type silicon substrate contains a donor including a group 15 element, an acceptor including a group 13 element, carbon, and oxygen. The n-type silicon substrate includes more atoms of the donor than atoms of the acceptor per unit volume, and more carbon atoms than oxygen atoms per unit volume. The donor has a greater segregation coefficient in silicon than the acceptor.