LED Seed Particle Epitaxy for Sapphire Substrate Recovery
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Solution Overview
Problem
The high material cost and limited reusability of sapphire substrates in traditional LED manufacturing processes, which contribute significantly to the overall cost of Light-Emitting Diodes (LEDs) and can damage the light-emitting structure during separation.
Innovation Solution
A method involving a printed circuit board as a substrate with a seed layer of miniature single-crystal elements for epitaxial growth of a group III-V semiconductor layer, allowing for theoretically limitless recycling of the substrate and reducing material costs by using a dielectric adhesion layer and etching process to detach the substrate without laser liftoff.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sapphire substrates are used for growing light-emitting structures, then the LED can be manufactured with traditional processes, but the material cost increases significantly and the substrate can be reused only limited times
Solution Approach 1:
The patent implements substrate recovery by growing a sacrificial layer on the sapphire substrate, allowing the light-emitting structure to be separated and the substrate to be reused for subsequent growth cycles. This directly addresses the limited reusability issue while managing material costs through repeated substrate utilization.
Solution Approach 2:
The patent segments the light-emitting structure from the sapphire substrate by introducing a sacrificial layer at the interface. This segmentation enables the substrate to be separated and recovered after the LED structure is formed, improving substrate reusability and reducing overall material costs.
2Ease of manufacture
If laser liftoff process is used to separate sapphire substrate from light-emitting structure, then the substrate can be separated, but the light-emitting structure can be damaged
Solution Approach 1:
The patent introduces a sacrificial layer as an intermediary between the sapphire substrate and the light-emitting structure. This sacrificial layer serves as a weak interface that allows easy separation through chemical etching without requiring laser liftoff, thereby preventing damage to the light-emitting structure while enabling substrate recovery.
3Ease of manufacture
If sapphire substrate is included with packaged LED, then the LED can be manufactured traditionally, but the overall material cost increases significantly
Solution Approach 1:
The patent enables substrate recovery and reuse by growing a sacrificial layer that facilitates separation. The sapphire substrate can be cleaned and reused for subsequent LED structure growth, significantly reducing the overall material cost while maintaining traditional manufacturing processes.
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 cost-effective LED production by eliminating the sapphire substrate's material cost and preventing damage to the light-emitting structure, facilitating efficient recycling and reducing manufacturing costs while maintaining the structural integrity of the LED.
Implementation Method 1
The miniature elements each contain a single-crystal material suitable for epitaxially growing the group III-V semiconductor layer
Data Source
AI summary
A device includes a substrate; a group III-V semiconductor layer disposed over the substrate; and a seed layer disposed over the group III-V semiconductor layer. The substrate is a printed circuit board. The group III-V semiconductor layer includes a multiple quantum well (MQW) layer, a p-type doped layer, and an n-type doped layer. The seed layer includes a plurality of miniature elements. The miniature elements each contain a single-crystal material suitable for epitaxially growing the group III-V semiconductor layer. The miniature elements collectively cover less than 100% of a surface of the group III-V semiconductor layer.