GaN LED Core-Shell Structure Transfer via Mechanical Post-Processing
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Solution Overview
Problem
Existing methods for manufacturing GaN-based light emitting devices face challenges such as low wet-etching selectivity, difficulties in transferring devices onto flexible substrates, mechanical contact issues with electrodes, and alignment problems that reduce light emitting efficiency.
Innovation Solution
A GaN-based light emitting device is fabricated using a core-shell structure with a flexible substrate, where a buried layer is formed between the flexible substrate and the first electrode, and the device is transferred from a nonflexible substrate using a post-mechanical treatment method that weakens the interface adhesion, allowing for high-precision alignment and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a sacrificing layer is used for transferring LED onto flexible substrate, then transferability is improved, but wet-etching selectivity deteriorates due to low selectivity between AlGaN/GaN layers
Solution Approach 1:
The patent extracts the transfer function from the sacrificing layer approach and implements it through a separate transfer substrate. The LED structure is grown on a first substrate, then transferred to a second flexible substrate, eliminating the need for wet-etching sacrificing layers while maintaining transferability.
Solution Approach 2:
The patent introduces a transfer substrate as an intermediary between the growth substrate and the final flexible substrate. This mediator enables the transfer process without requiring low-selectivity wet-etching, solving the contradiction between transferability and etching selectivity.
2Ease of operation
If electrodes are formed with simple mechanical contacts, then ease of assembly is improved, but contact reliability deteriorates due to poor ohmic contacts
Solution Approach 1:
The patent forms electrode contact holes and prepares ohmic contact structures during the LED growth process on the first substrate, before transfer. This preliminary action ensures reliable ohmic contacts are established in advance, which are then transferred together with the LED structure to the flexible substrate.
3Adaptability or versatility
If mesa structure is formed by etching sacrificing layer, then transferability is improved, but light emitting efficiency deteriorates due to surface recombination requiring high-precision alignment
Solution Approach 1:
The patent extracts the mesa structure formation from the wet-etching process and implements it through physical separation at the interface between the first and second substrates. This eliminates surface recombination issues associated with wet-etched mesa structures while maintaining transferability.
Solution Approach 2:
The patent replaces the chemical wet-etching mechanism with a mechanical separation approach. The LED structure is separated from the first substrate through physical detachment at the interface, avoiding the need for chemical etching and the associated surface recombination problems.
4Adaptability or versatility
If product is separated as individual component, then flexibility is improved, but transfer complexity increases due to need to contact with electrodes on another substrate
Solution Approach 1:
The patent merges the LED structure, electrode contacts, and transfer process into a single integrated operation. The entire LED structure with pre-formed electrode contacts is transferred as one unit from the first substrate to the second flexible substrate, eliminating the need for separate handling and alignment operations.
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 the production of high-efficiency, flexible, and large-area light emitting devices with improved alignment and reduced surface recombination, simplifying the manufacturing process by avoiding wet-etching and enhancing the overall efficiency of the LEDs.
Implementation Method 1
forming a first GaN layer having a difference in a coefficient of thermal expansion from the first GaN layer
Data Source
AI summary
Disclosed are GaN based light emitting devices and methods of manufacturing the same using post-mechanical treatment. The GaN based light emitting device includes first and second electrodes, and a flexible substrate which are sequentially stacked, an n-type GaN layer, an activation layer, and a p-type GaN layer interposed between the first and second electrodes and forming a core-shell structure, and a buried layer interposed between the flexible substrate and the first electrode, wherein the first electrode and the core-shell structure are buried in the buried layer.