Solar Cell Emitter Architecture With Dotted Diffusion Trenches
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Solution Overview
Problem
Existing solar cell manufacturing techniques face challenges in increasing efficiency and reducing costs, particularly in forming stable and efficient emitter regions with differentiated P-type and N-type architectures.
Innovation Solution
The implementation of a method that involves forming differentiated P-type and N-type silicon emitter regions with dotted diffusion, using laser ablation to pattern the emitters, and incorporating non-continuous trenches in the substrate to enhance breakdown performance and reduce power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional laser ablation is used to form uniform emitters, then emitter uniformity is improved, but material removal difficulty increases and reverse bias breakdown occurs
Solution Approach 1:
The emitter is divided into discrete dotted regions rather than forming a continuous uniform layer. The laser ablation process creates separate dotted emitters spaced apart, which reduces the continuous material removal difficulty and prevents reverse bias breakdown while maintaining uniformity through controlled dot placement and size
Solution Approach 2:
Different regions of the emitter are created with specific local properties - dotted regions with controlled spacing and size. This allows localized optimization of electrical properties while maintaining overall uniformity, addressing both manufacturing ease and precision requirements
2Reliability
If differentiated P-type and N-type architecture is implemented, then breakdown performance is improved, but fabrication process complexity increases
Solution Approach 1:
The emitter region is segmented into alternating P-type and N-type dotted regions. This segmentation creates the differentiated architecture that improves breakdown performance by preventing carrier accumulation, while the systematic patterning approach keeps the fabrication process manageable
Solution Approach 2:
The emitter structure employs asymmetric differentiation between P-type and N-type regions rather than symmetric uniform structure. This asymmetric dotted diffusion pattern creates the necessary electrical properties for improved breakdown performance
3Manufacturing precision
If dotted diffusion design is used, then breakdown voltage is reduced and uniformity is improved, but processing speed requirements increase
Solution Approach 1:
The laser ablation process maintains continuous operation while creating the dotted pattern. The systematic scanning and dot formation can be performed continuously across the substrate, maintaining high processing speed while achieving the required uniformity through controlled dot placement and size consistency
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 approach results in solar cells with improved breakdown performance, reduced reverse bias breakdown, and increased efficiency, while also simplifying the fabrication process and potentially lowering production costs.
Implementation Method 1
forming non-continuous trenches and alternating emitter regions using laser ablation
Data Source
AI summary
Methods of fabricating solar cell emitter regions with differentiated P-type and N-type architectures and incorporating dotted diffusion, and resulting solar cells, are described. In an example, a solar cell includes a substrate having a light-receiving surface and a back surface. A first polycrystalline silicon emitter region of a first conductivity type is disposed on a first thin dielectric layer disposed on the back surface of the substrate. A second polycrystalline silicon emitter region of a second, different, conductivity type is disposed on a second thin dielectric layer disposed in a plurality of non-continuous trenches in the back surface of the substrate.