Vertical LED Current Blocking Layer for Voltage Stability
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Solution Overview
Problem
Vertical light emitting diodes (LEDs) face issues with current concentration, leading to increased operating voltage and reduced light intensity, and low light extraction efficiency, which affects the reliability and performance of the devices.
Innovation Solution
Incorporating a current blocking layer made of insulating material, such as oxide, between the semiconductor layers to distribute current flow evenly and using nitride layers with varying refractive indices to enhance light extraction, the current blocking layer is formed by plasma oxidation and disposed between the second conductivity-type semiconductor layer and the ohmic contact layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a vertical LED structure is used with electrode layers applied to semiconductor layers, then the device structure is simplified and manufacturing is easier, but electric current concentrates on a lower side of the first electrode layer causing increased operating voltage and reduced light intensity
Solution Approach 1:
The patent introduces a current blocking layer with specific electrical properties at a localized position (between the first electrode layer and first conductivity-type semiconductor layer) to create non-uniform current distribution. This local modification prevents current concentration and ensures reliable operation without changing the overall vertical structure that provides manufacturing ease.
2Ease of manufacture
If a vertical LED structure is used with electrode layers applied to semiconductor layers, then the device structure is simplified and manufacturing is easier, but operating voltage increases due to current concentration
Solution Approach 1:
The current blocking layer is strategically positioned at a specific location within the vertical structure to locally control current flow. This localized intervention prevents current concentration pathways that would increase operating voltage, while maintaining the overall simple vertical architecture that enables easy manufacturing.
3Ease of manufacture
If a vertical LED structure is used with electrode layers applied to semiconductor layers, then the device structure is simplified and manufacturing is easier, but light intensity decreases due to current concentration
Solution Approach 1:
By introducing the current blocking layer at a specific position in the vertical structure, the patent locally modifies current distribution to prevent concentration effects. This ensures broader current flow across the active layer, enhancing light generation and intensity while preserving the manufacturing advantages of the vertical configuration.
4Adaptability or versatility
If light emitting diodes are used to convert electric signal into light, then the device functionality is achieved, but light extraction efficiency is low affecting performance
Solution Approach 1:
The current blocking layer is positioned to locally control current distribution in the region where light extraction occurs. By preventing current concentration, it ensures more uniform carrier injection and light generation throughout the active layer, improving the proportion of generated light that can be effectively extracted rather than lost.
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 stabilizes the operating voltage, prevents current concentration, and improves light extraction efficiency by ensuring even current distribution and effective light emission.
Implementation Method 1
the current blocking layer is formed by plasma oxidation
Implementation Method 2
using nitride layers with varying refractive indices to enhance light extraction
Data Source
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AI summary
In an embodiment, a light emitting device comprises: a second electrode layer; a second conductivity-type semiconductor layer on the second electrode layer; a current blocking layer comprising an oxide of the second conductivity-type semiconductor layer; an active layer on the second conductivity-type semiconductor layer; a first conductivity-type semiconductor layer on the active layer; and a first electrode layer on the first conductivity-type semiconductor layer.