Semiconductor Light Emitting Device Dielectric Layer Electrode Structure
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Solution Overview
Problem
Current semiconductor light emitting devices face challenges in enhancing light extraction efficiency, particularly due to limitations in the structure and materials used for the light emitting layer and electrodes, which affect the reflectance and current spread within the device.
Innovation Solution
The semiconductor light emitting device incorporates a dielectric layer with a refractive index lower than the semiconductor layer, along with a specific electrode structure comprising a first portion in contact with the semiconductor layer and a second portion on the dielectric layer, enhancing reflectance and current spread, thereby improving light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a crystal layer is joined to a conductive substrate and the substrate is removed with roughening processing, then light extraction efficiency is increased, but device complexity increases
Solution Approach 1:
The patent removes the substrate entirely and replaces it with a support substrate that provides only mechanical support, extracting the unnecessary functional elements (conductive substrate + roughening processing) while maintaining light extraction efficiency through the dielectric layer configuration
Solution Approach 2:
The patent changes the refractive index parameter of the layer in contact with the light emitting layer by introducing a dielectric layer with lower refractive index, which improves light extraction efficiency without requiring substrate removal and roughening processing
2Productivity
If no electrode is formed on the light extraction surface, then light extraction efficiency is improved, but current spread is insufficient
Solution Approach 1:
The patent applies local quality by forming the electrode only in specific regions (first and second regions) rather than uniformly across the light extraction surface, allowing light extraction in the third region while providing current injection in the first and second regions
Solution Approach 2:
The electrode is segmented into multiple portions (first portion in first region, second portion in second region) rather than forming a single continuous electrode, which improves both current spread and light extraction efficiency
3Productivity
If a dielectric layer with lower refractive index is introduced, then light extraction efficiency is increased, but device complexity increases
Solution Approach 1:
The dielectric layer serves multiple functions simultaneously: it acts as a refractive index management layer for light extraction, provides structural support, and enables electrode configuration, thereby reducing the need for separate components and offsetting the added complexity
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
This configuration significantly increases light extraction efficiency and reduces the resistance of the electrode, achieving a balance between light output and current distribution within the device.
Implementation Method 1
The dielectric layer contacts with the second surface and has a refractive index lower than a refractive index of the first semiconductor layer
Data Source
AI summary
According to one embodiment, a semiconductor light emitting device includes a first semiconductor layer, a second semiconductor layer, a light emitting layer, a dielectric layer, a first electrode, a second electrode and a support substrate. The first layer has a first and second surface. The second layer is provided on a side of the second surface of the first layer. The emitting layer is provided between the first and the second layer. The dielectric layer contacts the second surface and has a refractive index lower than that of the first layer. The first electrode includes a first and second portion. The first portion contacts the second surface and provided adjacent to the dielectric layer. The second portion contacts with an opposite side of the dielectric layer from the first semiconductor layer. The second electrode contacts with an opposite side of the second layer from the emitting layer.