Solar cell emitter region fabrication with differentiated P-type and N-type architectures and incorporating dotted diffusion
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Solution Overview
Problem
Conventional solar cell fabrication techniques face challenges in increasing efficiency and cost-effectiveness, particularly in forming stable P-type and N-type emitter regions with uniform reverse bias breakdown and high-density dot placement, which affects the breakdown voltage and manufacturing speed.
Innovation Solution
The implementation of differentiated P-type and N-type architectures with dotted diffusion, utilizing laser ablation or non-laser island diffusion, to create more stable and efficient emitter regions with controlled spot sizes and improved sidewall uniformity, enabling faster processing and reduced power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solar cell fabrication techniques are used to form P-type and N-type emitter regions, then the manufacturing process is simpler, but the reverse bias breakdown uniformity and breakdown voltage are insufficient
Solution Approach 1:
The patent divides the continuous emitter region into discrete dotted regions arranged in periodic patterns. This segmentation allows independent control of each dot's properties, enabling uniform reverse bias breakdown across the entire emitter while maintaining manufacturing feasibility through standardized dot fabrication processes
Solution Approach 2:
The patent implements different architectures for P-type and N-type emitter regions, with each type having optimized local properties. The dotted diffusion technique creates localized dopant regions with specific concentration profiles, allowing tailored electrical characteristics for each emitter type to achieve uniform breakdown behavior
2Power
If continuous emitter regions are used in conventional solar cells, then the fabrication process is faster, but the breakdown voltage is reduced and power losses increase
Solution Approach 1:
By segmenting the emitter into discrete dots rather than using continuous regions, the patent achieves higher breakdown voltage through reduced edge effects and improved field distribution. The dotted structure maintains manufacturing efficiency by using standardized periodic patterns that can be fabricated with conventional diffusion techniques
Solution Approach 2:
The patent transitions from two-dimensional continuous emitter planes to a patterned dotted structure that effectively utilizes spatial arrangement in multiple dimensions. This dimensional transformation allows optimization of electrical properties while maintaining manufacturing throughput through efficient pattern replication
3Reliability
If high-density dot placement is implemented in dotted diffusion, then the emitter efficiency is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent combines multiple fabrication steps into integrated processes, such as performing dopant diffusion and pattern formation in coordinated sequences. This merging approach ensures consistent dot placement and spacing while achieving high-density configurations, as the combined processes mutually reinforce precision requirements
Solution Approach 2:
The patent incorporates process control mechanisms that monitor and adjust dot formation parameters in real-time. Feedback from intermediate process measurements allows correction of placement variations, ensuring high manufacturing precision is maintained even at high dot densities
4Reliability
If differentiated P-type and N-type architectures are implemented, then the solar cell efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent applies differentiated architectures locally to P-type and N-type emitter regions, with each type optimized for its specific electrical characteristics. This localized differentiation improves overall cell efficiency while avoiding unnecessary complexity in regions where simpler structures would suffice
Solution Approach 2:
The dotted diffusion technique serves multiple functions simultaneously: it creates the emitter regions, defines the periodic patterns, controls dopant distribution, and establishes the spatial arrangement. This multi-functionality reduces the need for separate process steps, thereby limiting the increase in device complexity despite the differentiated architecture
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 enhances the breakdown voltage, reduces manufacturing time, and improves the uniformity and efficiency of solar cell production by eliminating the need for continuous emitters and simplifying the fabrication process.
Implementation Method 1
utilizing laser ablation or non-laser island diffusion, to create more stable and efficient emitter regions with controlled spot sizes
Implementation Method 2
dotted diffusion
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.