Flip-Chip LED Hole Layout for Current Crowding Relief
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Solution Overview
Problem
Conventional flip-chip light-emitting diodes (LEDs) experience current crowding and heat accumulation near the n-electrode, leading to reduced light-emitting performance and shortened service life due to localized heat generation.
Innovation Solution
The flip-chip LED design features an epitaxial structure with independent first and second regions, where the first region has a smaller surface area exposed by holes compared to the second region, allowing for more even current distribution and reduced heat accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional P/N structure with uniform via structures is used, then the manufacturing process is simple, but current crowding occurs near the n-electrode leading to localized heat generation and reduced light-emitting performance
Solution Approach 1:
The patent applies local quality by creating non-uniform via structures with different contact areas in different regions. Specifically, the first region has vias with a first contact area while the second region has vias with a second contact area, where the contact areas differ to regulate current flow distribution. This local variation in via structure prevents current crowding at the n-electrode while maintaining manufacturing feasibility through a systematic fabrication process.
2Power
If high current is applied to improve light-emitting efficiency, then the LED can withstand higher power, but current tends to accumulate at the region near the n-electrode causing localized heat generation
Solution Approach 1:
The patent applies parameter changes by modifying the via contact area parameter across different regions. The first region has vias with a first contact area and the second region has vias with a second contact area, where these contact area parameters are specifically designed to distribute current more evenly. This parameter variation allows the LED to handle high current while preventing localized heat accumulation by directing current through regions with appropriate contact areas.
3Ease of manufacture
If uniform via structures are used throughout the LED, then the manufacturing process is straightforward, but current does not spread evenly causing reduced service life
Solution Approach 1:
The patent applies segmentation by dividing the LED structure into distinct first and second regions with different via characteristics. The first region contains vias with a first contact area while the second region contains vias with a second contact area. This segmentation allows each region to be optimized for its specific function in current distribution, thereby extending service life through improved current spreading while maintaining a systematic fabrication approach.
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 design effectively alleviates current crowding and heat accumulation, enhancing the light-emitting efficiency and prolonging the service life of the flip-chip LED by ensuring more uniform current distribution and reduced thermal issues.
Implementation Method 1
Each of the first and second holes extends through the second semiconductor layer and the active layer, and terminates at and partially exposes the first semiconductor layer. The surface area of the first semiconductor layer exposed by the first holes is smaller than the surface area exposed by the second holes, causing current to flow more evenly
Implementation Method 2
The connecting electrode is disposed on the first insulating layer and within the first openings, and is electrically connected to the first semiconductor layer through the first opening
Implementation Method 3
Light-emitting diode (LED) is a semiconductor device that emits light energy generated by recombination of charge carriers
Data Source
AI summary
A flip-chip light-emitting diode includes an epitaxial structure including a first semiconductor layer, an active layer and a second semiconductor layer that are sequentially disposed on one another in such order. The epitaxial structure is formed with first holes and second holes respectively at a first region and a second region that are independent from each other. Each of the first and second holes extends through the second semiconductor layer and the active layer, and partially exposes the first semiconductor layer. A surface of the first semiconductor layer exposed by the first holes has a total area smaller than a total area of a surface of the first semiconductor layer exposed by the second holes.