Flip-Chip LED Electrode Geometry for Current Uniformity
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Solution Overview
Problem
Conventional sub-micron sized flip-chip LED devices face issues with uneven current spreading and low anti-electrostatic discharge capabilities, leading to low light-emission efficiency and reliability.
Innovation Solution
A light-emitting device design featuring a semiconductor structure with a mesa structure and strategically positioned contact electrodes, where the first contact electrode is on top of the mesa and electrically connected to the first semiconductor layer, and the second contact electrode, with a dot-like portion and auxiliary extending portions, is electrically connected to the second semiconductor layer, optimizing current distribution and anti-ESD characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flip-chip LED device structure is used, then device simplicity is maintained, but current spreading becomes uneven and anti-electrostatic discharge capability decreases
Solution Approach 1:
The second contact electrode is divided into multiple segments (second contact electrode segments) that are distributed across the semiconductor structure. This segmentation allows for better current distribution and improved anti-electrostatic discharge capability without significantly increasing overall device complexity.
Solution Approach 2:
Different regions of the contact electrodes are designed with different properties. The first contact electrode is positioned at the mesa structure for optimal electrical connection to the first semiconductor layer, while the second contact electrode segments are strategically placed on the second semiconductor layer to optimize current spreading and ESD protection in specific local areas.
2Productivity
If contact electrodes are positioned to optimize current spreading, then light-emission efficiency improves, but device structure complexity increases
Solution Approach 1:
The contact electrodes are arranged in a specific geometric configuration where the first contact electrode and second contact electrode segments create defined spatial relationships. When projected on an imaginary plane, they form parallel lines with specific distance ratios (0.3-1.0), optimizing current spreading in multiple dimensions without requiring complex three-dimensional structures.
3Reliability
If mesa structure is formed to expose first semiconductor layer, then current distribution is improved, but manufacturing precision requirements increase
Solution Approach 1:
The invention specifies particular parameter ranges for the mesa structure and contact electrode positioning to optimize current distribution while maintaining manufacturability. The distance ratio parameter (L2/L1 or d2/d1) is controlled within the range of 0.3-1.0, providing a practical manufacturing window that balances performance optimization with fabrication feasibility.
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 current spreading and anti-electrostatic discharge capabilities, resulting in improved light-emission efficiency and reliability by balancing current distribution and preventing electrostatic discharge, thus stabilizing saturation current and ensuring higher luminous efficacy.
Implementation Method 1
The first contact electrode is located on top of the mesa structure and electrically connected to the first semiconductor layer. The second contact electrode is located on top of and electrically connected to the second semiconductor layer.
Implementation Method 2
Light-emitting diodes (LEDs) are solid-state semiconductor devices that convert electrical energy into visible light through the combination of holes provided by a p-type semiconductor and electrons provided by an n-type semiconductor.
Data Source
AI summary
A light-emitting device includes a semiconductor structure having a first semiconductor layer, an active layer, and a second semiconductor layer. The second semiconductor layer and the active layer formed on a top surface of the first semiconductor layer exposes a portion of the top surface. A first strip electrode is connected to the exposed top surface. A second strip electrode is connected to the second semiconductor layer. When first and second electrodes are projected on a plane, two parallel lines, that contact two opposite ends of the first electrode and perpendicularly intersect a straight line connecting between two opposite ends of the second electrode, define on the straight line a length, which does not extend beyond a distance between the two opposite ends of the second electrode.