LED Trench Electrode for Light Extraction and Current Distribution
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Solution Overview
Problem
Conventional light-emitting diodes (LEDs) face challenges in optimizing light extraction efficiency and current distribution due to internal reflection and current crowding effects, which affect their performance and efficiency.
Innovation Solution
The design incorporates a substrate with a semiconductor stack and a trench that separates regions, allowing for a first electrode to extend across the trench, improving light extraction by exposing the substrate surface and reducing current crowding through a conductive layer and current blocking layer configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional LED structure is used, then the device is simple to manufacture, but light extraction efficiency is reduced due to internal reflection
Solution Approach 1:
The patent introduces a trench structure that divides the LED device into distinct regions (first region with n-type semiconductor layer, second region with p-type semiconductor layer). This segmentation allows different portions of the device to be optimized independently, with the trench exposing the substrate to reduce internal reflection and improve light extraction efficiency while maintaining manufacturing feasibility through standardized fabrication processes
2Loss of energy
If a trench structure is introduced to improve light extraction, then light extraction efficiency increases, but device complexity increases
Solution Approach 1:
The patent utilizes the vertical dimension by etching a trench from the top surface down to expose the substrate. This vertical feature creates additional light extraction pathways without significantly expanding the planar footprint of the device. The trench structure adds dimensional complexity but maintains relative structural simplicity through symmetric design and integration with the semiconductor layer stacking sequence
3Reliability
If current blocking layer is added to control current distribution, then current crowding is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent applies current blocking layers selectively in specific regions rather than uniformly across the entire device. The first current blocking layer is positioned in the first region and the second current blocking layer in the second region, with each layer having specific thickness ranges (50-200 nm and 100-300 nm respectively). This localized application controls current distribution in problem areas while maintaining simplicity in other regions, balancing reliability improvement with manufacturing 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
This configuration enhances light extraction efficiency and current distribution, leading to improved LED performance and increased power handling capabilities.
Implementation Method 1
for emitting light under the principle of transforming electrical energy to optical energy by injecting electrons and holes through the n-type semiconductor layer and the p-type semiconductor layer respectively to the active layer to perform radiative combination and emit light
Data Source
AI summary
A light-emitting device is provided. The light-emitting device comprises a substrate; a semiconductor stack on the substrate comprising a first region and a second region; a first trench extending from the semiconductor stack to the substrate to expose a surface of the substrate and separating the first region from the second region; and a first electrode comprising a first pad on the first region and a first extending electrode connecting to the first pad, wherein the first extending electrode is across the first trench.