LED Chamfer Geometry for ESD-Resistant Light-Emitting Mesa
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Solution Overview
Problem
The increased luminous brightness of light-emitting diodes (LEDs) has led to reduced product reliability due to enhanced tip effects, which concentrate electrons and electron holes, weakening anti-electro-static discharge (ESD) ability and causing ESD breakdown and chiplet leakage.
Innovation Solution
The design optimizes the chamfer portion of the light-emitting region by introducing an arc-shaped chamfer and defining the radius of curvature, ensuring uniform carrier distribution and maintaining a sufficient distance between the electrode and the light-emitting mesa to prevent electro-static breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the area of the light-emitting region is increased to improve luminous brightness, then the luminous output per watt increases, but the spacing between the light-emitting region and other functional structures becomes smaller, leading to poor electric field distribution uniformity and enhanced tip effect
Solution Approach 1:
The patent applies curvature by designing the chamfer portion of the light-emitting region with a specific radius of curvature (R≥√2L). This curved geometry eliminates sharp corners that cause electric field concentration, thereby reducing the tip effect and improving ESD resistance while maintaining the required light-emitting area.
Solution Approach 2:
The patent changes the geometric parameters of the chamfer portion by defining a minimum radius of curvature (R≥√2L) and optimizing its position and dimensions. This parameter optimization allows the structure to maintain large light-emitting area while ensuring sufficient spacing and uniform electric field distribution at critical regions.
2Illumination intensity
If the light-emitting region area is increased to enhance luminous brightness, then more light output is achieved, but the tip effect is enhanced causing electron and electron hole concentration at the tip region
Solution Approach 1:
The curved chamfer design with radius R≥√2L replaces sharp corners with smooth transitions, distributing the electric field more uniformly and preventing charge carrier concentration at tip regions, thereby reducing the harmful tip effect while maintaining brightness.
Solution Approach 2:
The patent applies different geometric characteristics to different regions: the light-emitting region maintains large area for brightness, while the chamfer portion uses curved geometry with specific radius to locally address electric field distribution and reduce tip effect at critical transition zones.
3Volume of moving object
If the spacing between light-emitting region and other functional structures is reduced to maintain chiplet size, then chiplet dimensions are controlled, but electric field distribution uniformity deteriorates and ESD breakdown risk increases
Solution Approach 1:
The curved chamfer design creates smooth transitions that prevent electric field concentration, allowing smaller spacing between structures while maintaining uniform electric field distribution and ESD resistance, thus enabling compact chiplet design without sacrificing reliability.
Solution Approach 2:
The optimized chamfer structure proactively prevents ESD breakdown by eliminating sharp corners that would cause electric field concentration, thereby preemptively protecting against electro-static discharge damage in compact chiplet designs.
Data Source
AI summary
A light-emitting diode and a light-emitting device are provided. The light-emitting diode includes a semiconductor stack layer and a first electrode. The semiconductor stack layer has a light output surface and a back surface opposite to each other. On the back surface, the semiconductor stack layer has a first mesa exposing a first semiconductor layer thereof and a second mesa adjacent to the first mesa. The first electrode formed on the back surface of the semiconductor stack layer at least surrounds a portion of the second mesa, and the first electrode surrounding a portion of the second mesa extends toward the light output surface. The first electrode has a first chamfer portion, and the second mesa has a second chamfer portion. The first electrode and the second mesa have a minimum distance L, and a radius of curvature of the second chamfer portion is greater than or equal to √{square root over (2)}L.