LED Pad and Via Layout for Uniform Light and Lower Forward Voltage
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Solution Overview
Problem
Conventional light-emitting diodes (LEDs) face challenges in uniform light distribution and high forward voltage due to limitations in semiconductor stack design and contact layer configurations, which affect their efficiency and performance.
Innovation Solution
The proposed light-emitting device features a semiconductor stack with a first and second semiconductor layer and an active layer, along with vias and insulating layers, where the contact layer covers the vias and extends over the second semiconductor layer, and pads are strategically positioned to distribute light uniformly and reduce forward voltage. This configuration includes a reflective structure and insulating layers to enhance light emission and electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional semiconductor stack design and contact layer configurations are used, then manufacturing is simpler, but light distribution is non-uniform and forward voltage is high
Solution Approach 1:
The contact layer is divided into multiple separate contact regions rather than a single continuous layer. Each contact region is positioned over specific semiconductor regions, creating discrete electrical contact points that enable non-uniform current distribution to achieve uniform light emission across the LED structure.
Solution Approach 2:
Different regions of the contact layer are designed with different properties - some regions have higher conductivity or different thickness to compensate for non-uniform light emission in specific areas. This local variation in contact layer characteristics allows targeted control of current density to achieve overall uniform light distribution.
2Power
If conventional contact layer configurations are used, then device structure is simpler, but forward voltage remains high
Solution Approach 1:
The contact layer is segmented into multiple discrete contact regions that can be independently optimized. This segmentation allows each contact region to be tailored for optimal electrical contact with underlying semiconductor regions, reducing overall forward voltage through improved current injection efficiency.
Solution Approach 2:
The contact layer design extends beyond a simple planar configuration by incorporating vertical thickness variations and three-dimensional positioning relative to the semiconductor stack. This multi-dimensional approach enables better electrical contact and lower forward voltage by optimizing the contact geometry in both horizontal and vertical dimensions.
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 achieves improved light distribution and reduced forward voltage, leading to increased efficiency and performance of the light-emitting device, with the pads and contact layers ensuring effective electrical connections and stable light emission.
Implementation Method 1
a reflective structure covering the second semiconductor layer
Data Source
AI summary
A light-emitting device includes a semiconductor stack including a first semiconductor layer, a second semiconductor layer, and an active layer between the first semiconductor layer and the second semiconductor layer; one or multiple vias penetrating the active layer and the second semiconductor layer to expose the first semiconductor layer; a first contact layer covering the one or multiple vias; a third insulating layer including a first group of one or multiple third insulating openings on the second semiconductor layer to expose the first contact layer; a first pad on the semiconductor stack and covering the first group of one or multiple third insulating openings; and a second pad on the semiconductor stack and separated from the first pad with a distance, wherein the second pad is formed at a position other than positions of the one or multiple vias in a top view of the light-emitting device.