Solar Cell Tunnel Passivation Without Laser Mask Etching
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Solution Overview
Problem
Existing solar cell manufacturing methods involving large-area laser etching for forming mask layers are costly and can cause damage to the semiconductor substrate, leading to inconsistent texturing and reflectivity differences between different regions, affecting efficiency and increasing production costs.
Innovation Solution
A method is introduced that forms a bifacial tunneling passivation structure by oxidizing the surface of the second passivation contact material layer in the passivation contact region to create a mask layer, allowing for localized processing without large-area laser etching, thereby reducing manufacturing costs and maintaining consistent texturing across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If large-area laser etching is used to form mask layers, then the mask layer can be formed for processing, but the manufacturing cost increases and the semiconductor substrate is damaged
Solution Approach 1:
The patent uses a sacrificial oxide layer as a disposable mask layer that is formed through chemical oxidation rather than expensive laser etching. This oxide layer serves its masking function temporarily during processing and is then removed, eliminating the need for costly and damaging laser etching operations while maintaining precise pattern formation.
Solution Approach 2:
The patent changes the physical and chemical parameters of the passivation contact material layer by controlling oxidation conditions (temperature, time, atmosphere) to form a mask layer with specific properties. This chemical transformation approach replaces the mechanical/thermal laser etching process, reducing cost and substrate damage while achieving the required masking precision.
2Manufacturing precision
If large-area laser etching is used to form mask layers, then the mask layer can be formed for processing, but the substrate is damaged leading to inconsistent texturing
Solution Approach 1:
The sacrificial oxide layer acts as a temporary, disposable mask that protects the substrate during processing. Unlike laser etching that directly damages the substrate, this oxide-based mask can be formed without damage and is subsequently removed, preserving substrate integrity and ensuring consistent texturing across the entire surface.
Solution Approach 2:
The oxide layer serves as an intermediary masking material that mediates between the processing requirements and the substrate. It provides the necessary masking function during etching or deposition processes without the harmful side effects of laser etching, thereby protecting the substrate and maintaining uniform texturing properties.
3Manufacturing precision
If large-area laser etching is used, then mask layer formation is achieved, but reflectivity differences between regions increase
Solution Approach 1:
The oxide-based sacrificial mask provides a uniform masking layer across the substrate surface that can be formed through controlled oxidation. This approach eliminates the localized damage and reflectivity variations caused by laser etching, resulting in more uniform reflectivity across different regions of the solar cell while simplifying the overall processing approach.
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 method enhances solar cell efficiency by forming a bifacial tunneling passivation structure while reducing manufacturing costs and minimizing substrate damage, resulting in reduced reflectivity differences between regions.
Implementation Method 1
The tunnel oxide layer allows majority carriers (e.g., electrons) to tunnel into the polysilicon layer while blocking the recombination of minority carriers (e.g., holes)
Implementation Method 2
oxidizing a surface of the second passivation contact material layer located in the passivation contact region to form a mask layer
Data Source
AI summary
A method for preparing a solar cell includes: providing an n-type semiconductor substrate, the semiconductor substrate including a first surface and a second surface opposite to each other, the second surface including a passivation contact region and a passivation region adjacent to each other; forming a first tunneling passivation structure on the first surface; forming a second tunnel material layer and a second passivation contact material layer stacked on the second surface; oxidizing a surface of the second passivation contact material layer located in the passivation contact region to form a mask layer; and processing the second passivation contact material layer located in the passivation region through the mask layer to form a second tunneling passivation structure located in the passivation contact region.