Mesa LED Current-Spreading Structure for Uniform Display Brightness
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Solution Overview
Problem
Conventional light-emitting devices for display applications face challenges in achieving high brightness and uniform current distribution across semiconductor mesas, leading to suboptimal image quality and efficiency.
Innovation Solution
A light-emitting device design featuring a semiconductor stack with mesas of different conductivity types, a contact metal structure, insulating structures, and current spreading electrodes to facilitate uniform current distribution and improved light extraction, along with an electrode pad structure for efficient electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional light-emitting devices are used for display applications, then the device structure is relatively simple, but the brightness uniformity and current distribution across semiconductor mesas are poor
Solution Approach 1:
The device segments the semiconductor structure into multiple mesas with different conductivity types (n-type and p-type) arranged in an alternating pattern. This segmentation allows independent control and optimization of current distribution in different regions, improving brightness uniformity across the display device while managing the overall structural complexity through systematic arrangement.
Solution Approach 2:
The patent implements local quality by creating regions with different conductivity types (n-type and p-type mesas) in specific alternating patterns. Each local region has optimized electrical properties tailored to its function, with n-type mesas providing electron injection and p-type mesas providing hole injection, thereby achieving uniform current distribution and improved brightness uniformity across the entire device.
2Reliability
If conventional contact metal structures are used, then the manufacturing process is simpler, but the electrical connection efficiency and current distribution uniformity are insufficient
Solution Approach 1:
The contact metal structure is segmented into multiple independent contact regions corresponding to different mesas, with each contact region providing dedicated electrical connection. This segmentation improves electrical connection efficiency by ensuring reliable contact with each semiconductor mesa while allowing standardized manufacturing processes to be applied repeatedly across the device.
Solution Approach 2:
The contact metal structure serves multiple functions: providing electrical connection to individual mesas, distributing current uniformly across the semiconductor structure, and enabling independent control of different conductivity type regions. This multi-functionality improves reliability while the contact metal can be formed using standard sputtering or evaporation techniques.
3Manufacturing precision
If uniform current distribution across semiconductor mesas is not optimized, then the device structure remains simple, but the image quality and color accuracy are suboptimal
Solution Approach 1:
The semiconductor structure is segmented into multiple mesas with alternating conductivity types, allowing precise control of current distribution in each region. This segmentation enables optimized injection of carriers (electrons and holes) into specific regions, improving recombination efficiency and light emission uniformity, thereby enhancing image quality and color accuracy.
Solution Approach 2:
Each mesa region is assigned specific conductivity type (n-type or p-type) to optimize local electrical properties and carrier injection. This local optimization ensures uniform current distribution across the entire device, with each region contributing to high-quality image display and accurate color reproduction through controlled electroluminescence.
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
The design enhances brightness and uniformity of light emission, improving image quality and efficiency by ensuring consistent current distribution across the semiconductor mesas, thereby increasing the resolution and color accuracy of display devices.
Implementation Method 1
a current spreading electrode formed on the first insulating structure, including a first current spreader and a plurality of second current spreaders, wherein the first current spreader is located between the mesas and filled in the first openings to connect the first contact parts and the second current spreaders are formed on the mesas and filled in the second openings to connect the second contact parts
Implementation Method 2
a semiconductor stack, including a first semiconductor layer and a plurality of mesas spaced apart from each other on the first semiconductor layer, wherein the plurality of mesas each includes a second semiconductor layer, the first semiconductor layer and the second semiconductor layer have different conductivity types
Data Source
AI summary
A light-emitting device includes: a semiconductor stack, including a first semiconductor layer and a plurality of mesas spaced apart from each other on the first semiconductor layer, wherein the plurality of mesas each includes a second semiconductor layer, the first semiconductor layer and the second semiconductor layer have different conductivity types; a contact metal formed on the semiconductor stack, including a plurality of first contact parts located between the mesas and electrically connected to the first semiconductor layer, and a plurality of second contact parts located on the mesas and electrically connected to the second semiconductor layer; a first insulating structure formed on the contact metal, including a plurality of first openings corresponding to the first contact parts and a plurality of second openings corresponding to the second contact parts; a current spreading electrode formed on the first insulating structure, including a first current spreader and a plurality of second current spreaders, wherein the first current spreader is located between the mesas and filled in the first openings to connect the first contact parts and the second current spreaders are formed on the mesas and filled in the second openings to connect the second contact parts; a second insulating structure formed on the current spreading electrode, including a third opening on the first current spreader and a plurality of fourth openings formed on the second current spreaders; and an electrode pad structure formed on the second insulating structure, including at least one first electrode pad filled in the third opening to connect to the first current spreader, and a plurality of second electrode pads filled in the fourth openings to connect the second current spreaders.