MicroLED Isolation via Thin Sub-Structure Segmentation
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Solution Overview
Problem
Traditional microLED fabrication techniques result in wavelength shift and reduction in quantum efficiency due to etching through the pre-isolation LED layer structure, limiting the density and efficiency of light emission.
Innovation Solution
A method involving a shallow etch process that forms thick and thin sub-structures on the semiconductor substrate, where the thin sub-structures electrically isolate the microLEDs while maintaining the active region intact, preventing mobility of free electron carriers and preserving the original light emission characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional etching process is used to isolate microLEDs, then microLED density can be increased, but wavelength shift and quantum efficiency reduction occur
Solution Approach 1:
The patent divides the isolation structure into two segments: thick sub-structures that provide physical separation and thin sub-structures that provide electrical isolation. This segmentation allows each component to perform its specific function optimally - thick structures prevent carrier diffusion while thin structures minimize impact on the active region, thereby maintaining microLED density without compromising wavelength stability or quantum efficiency
Solution Approach 2:
The patent applies different structural qualities at different locations: thick sub-structures are positioned where maximum isolation is needed (between adjacent microLEDs), while thin sub-structures are positioned closer to the active region where minimal interference is required. This local differentiation enables effective electrical isolation while preserving the integrity and emission characteristics of the active region
2Reliability
If etching through active region is performed for isolation, then microLEDs are electrically isolated, but light extraction efficiency decreases
Solution Approach 1:
The patent applies partial action by forming thin sub-structures that provide sufficient electrical isolation without completely removing the material between microLEDs. The thin sub-structures extend only partially through the layer structure, stopping before completely separating the active regions. This partial isolation achieves the necessary electrical separation while leaving enough material intact to maintain light extraction efficiency and preserve the active region's optical properties
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 enhances light extraction efficiency and maintains the desired wavelength range, allowing for higher density and efficient light emission at reduced device sizes, with individually addressable microLEDs that retain the integrity of the original epitaxial layer structure's efficiency and wavelength.
Implementation Method 1
Each one of the plurality of thin sub-structures is configured for preventing mobility of free electron carriers therethrough to electrically isolate each one of the thick sub-structures from every other one of the thick sub-structures
Implementation Method 2
Active quantum wells (QWs) 130 are formed on bulk or prep layers 120... enabling the formation of an active region with desired light emission characteristics
Data Source
AI summary
A light emission system includes an array of micro light-emitting diodes (microLED)s. The array of microLEDs includes a semiconductor substrate, a prep layer formed on at least a portion of the semiconductor substrate, and an active region formed on the prep layer. The array of microLEDs also include a plurality of thick sub-structures forming an array on the active region, and a plurality of thin sub-structures formed on the active region, each one of the thin sub-structures being located between each adjacent pair of thick substructures. Each one of the thick sub-structures defines a shape and size of a corresponding one of the microLEDs. Each one of the thin sub-structures is configured for preventing mobility of free electron carriers therethrough to electrically isolate each one of the thick sub-structures from every other one of the thick sub-structures. Further, the plurality of microLEDs share the active region.