Wafer-Level Interconnection of Inverted Metamorphic Solar Cells
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Solution Overview
Problem
Current solar cell technologies face challenges in achieving high power and energy conversion efficiency, particularly in sophisticated applications like satellite power systems, due to limitations in material choice and fabrication processes for inverted metamorphic multijunction solar cells, leading to issues with assembly costs, yield losses, and less than ideal packing density.
Innovation Solution
A method for forming a multijunction solar cell array by growing subcells on a substrate in reverse sequence, using a surrogate substrate as a carrier, and interconnecting them to form discrete solar cells with graded interlayers, allowing for improved lattice constant transition and reduced threading dislocations, thereby enhancing energy conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If individual solar cells are assembled from separately fabricated cells bonded onto a platform, then assembly flexibility is improved, but assembly costs increase and yield losses occur
Solution Approach 1:
The patent performs interconnection operations before final assembly by forming conductive pathways and bonding structures on the solar cell substrates while they are still in wafer form. This preliminary interconnection eliminates the need for costly post-assembly bonding operations and reduces yield losses by identifying and correcting interconnection issues before final cell separation.
Solution Approach 2:
The patent combines multiple fabrication operations into a unified wafer-level process. Instead of separately fabricating individual cells and then assembling them, the method integrates cell formation, interconnection structure creation, and electrical bonding into a single continuous process that operates on entire wafers simultaneously, thereby reducing assembly costs and improving manufacturing efficiency.
2Adaptability or versatility
If individual solar cells are assembled from separately fabricated cells, then manufacturing flexibility is improved, but productivity decreases due to multiple assembly steps
Solution Approach 1:
The patent performs interconnection operations before final assembly by forming conductive pathways and bonding structures on the solar cell substrates while they are still in wafer form. This preliminary interconnection eliminates the need for costly post-assembly bonding operations and reduces yield losses by identifying and correcting interconnection issues before final cell separation.
Solution Approach 2:
The patent combines multiple fabrication operations into a unified wafer-level process. Instead of separately fabricating individual cells and then assembling them, the method integrates cell formation, interconnection structure creation, and electrical bonding into a single continuous process that operates on entire wafers simultaneously, thereby reducing assembly costs and improving manufacturing efficiency.
3Ease of manufacture
If conventional interconnection methods are used for solar cell arrays, then manufacturing simplicity is maintained, but packing density decreases
Solution Approach 1:
The patent transitions from planar interconnection methods to three-dimensional vertical interconnection structures. Conductive pathways are formed that extend through the thickness of the solar cell substrates, allowing electrical connections to be made in the vertical dimension rather than requiring extensive lateral routing. This dimensional transition enables tighter cell packing while maintaining manufacturing simplicity.
Solution Approach 2:
The patent implements nested interconnection structures where conductive pathways are embedded within the solar cell substrate layers themselves. The interconnection structures are integrated into the cell architecture, with conductive materials nested within semiconductor layers and bonding structures embedded within the cell stack, thereby maximizing packing density without complicating the manufacturing process.
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 enables higher efficiency solar cell arrays with improved packing density and reduced assembly costs, addressing the limitations of existing technologies by optimizing the interconnection and material growth processes for enhanced power and energy conversion.
Implementation Method 1
depositing on the first substrate a sequence of layers of semiconductor material forming a solar cell structure
Implementation Method 2
Photovoltaic cells, also called solar cells, are one of the most important new energy sources that have become available in the past several years
Data Source
AI summary
A method of forming a plurality of discrete, interconnected solar cells mounted on a carrier by providing a first semiconductor substrate; depositing on the first substrate a sequence of layers of semiconductor material forming a solar cell structure; forming a metal back contact layer over the solar cell structure; mounting a carrier on top of the metal back contact; removing the first substrate; and lithographically patterning and etching the solar cell structure to form a plurality of discrete solar cells mounted on the carrier.