PV Structure Fabrication with Integrated TCO and Metallic Seed Layers
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Solution Overview
Problem
Current solar cell manufacturing facilities are not optimized for large-scale production, leading to inefficiencies in the fabrication process, particularly in the deposition and annealing of transparent conductive oxide (TCO) layers and metallic grids, which affects production throughput and the quality of photovoltaic structures.
Innovation Solution
A system that integrates physical vapor deposition (PVD) tools to sequentially deposit TCO and metallic layers on a Si substrate without removing the substrate, followed by electroplating and high-temperature, rapid annealing of the metallic grids, allowing for simultaneous deposition and annealing of TCO and metallic seed layers, thereby streamlining the fabrication process and improving adhesion and film quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional manufacturing facilities are used for solar cell production, then existing equipment can be utilized, but production throughput is insufficient for large-scale manufacturing
Solution Approach 1:
The patent combines multiple deposition chambers into a single integrated facility, allowing sequential deposition of TCO layers and metallic seed layers without breaking vacuum. This merging of functions increases production throughput while managing facility complexity through unified system design.
Solution Approach 2:
The deposition facility is designed to perform multiple functions: depositing TCO layers, depositing metallic seed layers, and enabling subsequent electroplating all within the same system. This multi-functionality improves productivity by eliminating the need for separate specialized facilities.
2Manufacturing precision
If TCO layers are deposited using conventional methods, then standard deposition processes can be used, but film quality and optical properties are suboptimal
Solution Approach 1:
The patent employs specific deposition parameters including controlling oxygen partial pressure, deposition temperature, and layer thickness to optimize TCO film quality. These parameter changes enhance optical properties and reduce resistivity while managing manufacturing complexity through precise control.
Solution Approach 2:
The patent creates composite structures by depositing multiple TCO layers with different compositions and properties, then combining them with metallic seed layers. This composite approach optimizes both optical properties and electrical conductivity, achieving superior film quality through material combination.
3Reliability
If metallic grids are electroplated without a seed layer, then the process is simpler, but adhesion and reliability are insufficient
Solution Approach 1:
The patent introduces a metallic seed layer as an intermediary between the TCO layer and the electroplated metallic grid. This seed layer improves adhesion and reliability of the final metallic grid structure, while the added complexity is managed through the sequential deposition process within the same facility.
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 increases production throughput, enhances the optical and electrical properties of TCO layers, reduces resistivity, and improves the reliability of metallic grids, resulting in higher-efficiency photovoltaic structures with improved transparency and lower resistivity.
Implementation Method 1
a physical vapor deposition tool configured to sequentially deposit a transparent conductive oxide layer and a metallic layer on an emitter layer
Implementation Method 2
an electroplating tool configured to plate a metallic grid on the metallic layer
Implementation Method 3
a thermal annealing tool configured to anneal the transparent conductive oxide layer
Data Source
AI summary
One embodiment of the present invention can provide a system for fabrication of a photovoltaic structure. The system can include a physical vapor deposition tool configured to sequentially deposit a transparent conductive oxide layer and a metallic layer on an emitter layer formed in a first surface of a Si substrate, without requiring the Si substrate to be removed from the physical vapor deposition tool after depositing the transparent conductive oxide layer. The system can further include an electroplating tool configured to plate a metallic grid on the metallic layer and a thermal annealing tool configured to anneal the transparent conductive oxide layer.