Curved Finger Electrode Layout for LED ESD Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional light-emitting devices are prone to failure due to electrostatic discharge (ESD) and Electrical Over Stress (EOS) caused by electrical overload, leading to current crowding at sharp corners of electrodes, which reduces ESD tolerance and EOS endurance, resulting in damage such as electrode metal migration or epitaxy breakdown.
Innovation Solution
The design incorporates a pad electrode with a periphery and a finger electrode featuring a first portion extended from the periphery with a curvature radius larger than 10 μm, allowing for uniform current distribution and improved ESD tolerance by avoiding local current crowding, while maintaining light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrode structures with sharp corners are used, then manufacturing is simpler, but current crowding occurs at sharp corners leading to reduced ESD tolerance and EOS endurance
Solution Approach 1:
The patent applies curvature by designing the finger electrode with a rounded first side having a curvature radius of 0.5 μm to 30 μm instead of sharp corners. This curved geometry eliminates current crowding at electrode corners, uniformly distributes current density, and significantly improves ESD tolerance and EOS endurance while maintaining manufacturing feasibility through standard photolithography processes.
2Reliability
If the curvature radius of the finger electrode is increased to improve current distribution, then ESD tolerance improves, but the area of the electrode decreases
Solution Approach 1:
The patent optimizes the curvature radius parameter within a specific range of 0.5 μm to 30 μm to achieve the best balance between ESD tolerance and electrode area. This parameter optimization ensures sufficient current distribution improvement while maintaining adequate electrode area for electrical connection and light extraction efficiency.
3Reliability
If the first side length is reduced to minimize current crowding, then ESD tolerance improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies the first side length within a range of 0.5 μm to 30 μm, providing design flexibility that accommodates normal manufacturing variations. This parameter range ensures ESD tolerance improvement while remaining compatible with standard photolithography manufacturing capabilities and tolerance levels.
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 proposed electrode structure enhances ESD tolerance and EOS endurance by distributing current uniformly, reducing the risk of device failure and maintaining light extraction efficiency, as demonstrated by improved performance in ESD and EOS testing.
Implementation Method 1
a finger electrode connected to the pad electrode, wherein the finger electrode includes a first portion extended from the periphery of the pad electrode and a second portion away from the pad electrode, the first portion includes a first side and a second side, the first side is opposite to the second side, the first side includes a first arc having a first curvature radius, and the first curvature radius is larger than 10 μm
Implementation Method 2
The principle of LED is to transform electrical energy to optical energy by applying electrical current to LED and injecting electrons and holes to the active layer. The combination of electrons and holes in the active layer emits light accordingly.
Data Source
AI summary
A light-emitting device comprises a semiconductor stack; a pad electrode comprising a periphery disposed on the semiconductor stack; and a finger electrode connected to the pad electrode, wherein the finger electrode comprises a first portion extended from the periphery of the pad electrode and a second portion away from the pad electrode, the first portion comprises a first side and a second side, the first side is opposite to the second side, the first side comprises a first arc having a first curvature radius, and the first curvature radius is larger than 10 μm.