Nitride LED Electrode Layout for Suppressing Current Concentration
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Solution Overview
Problem
Nitride semiconductor light-emitting elements experience current concentration due to increased sheet resistance in thin n-type nitride semiconductor layers or when using AlGaN layers, leading to reduced luminance efficiency and reliability, and existing solutions like adding a high-resistance layer on the p-type semiconductor layer increase drive voltage and manufacturing costs.
Innovation Solution
The configuration of semiconductor layers and electrodes is optimized by arranging first and second conductivity type electrodes with specific contact regions, where the perimeter lengths of the first contact region are shorter than those of the second contact region, and the third contact region is designed to sandwich the first electrode, ensuring uniform current diffusion and emission without increasing drive voltage or manufacturing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-resistance layer is arranged on the surface of the p-type semiconductor layer to adjust resistance balance, then current concentration is alleviated, but drive voltage increases and luminous efficiency decreases
Solution Approach 1:
The patent applies local quality by creating an asymmetric contact region configuration where only specific portions of the electrodes have extended contact areas. The first contact region and third contact region are designed with different perimeter lengths relative to the second contact region, allowing localized resistance adjustment without adding global high-resistance layers that would increase drive voltage.
Solution Approach 2:
The patent employs asymmetry by designing the first contact region and third contact region with different perimeter lengths compared to the second contact region. This asymmetric configuration creates intentional resistance imbalance that compensates for the inherent resistance differences in the semiconductor layers, achieving current uniformity without additional manufacturing steps.
2Reliability
If a high-resistance layer is arranged on the surface of the p-type semiconductor layer, then current concentration is alleviated, but manufacturing cost increases due to additional manufacturing steps
Solution Approach 1:
The patent merges the electrode formation process with the resistance balance adjustment by integrating the asymmetric contact region configuration into the existing electrode manufacturing steps. The first, second, and third contact regions are formed as part of the same manufacturing sequence, eliminating the need for separate high-resistance layer deposition and patternization steps.
Solution Approach 2:
The electrode contact regions serve multiple functions: they provide electrical connection and simultaneously adjust resistance balance through their asymmetric configuration. This multi-functionality eliminates the need for separate resistance adjustment layers or additional manufacturing steps, reducing device complexity while maintaining current uniformity.
3Reliability
If the n-type nitride semiconductor layer has thin film thickness or uses AlGaN material, then sheet resistance increases causing significant current concentration, but maintaining thin layers is necessary for device performance
Solution Approach 1:
The patent addresses sheet resistance issues by transitioning from controlling resistance through material composition and thickness (vertical dimension) to controlling resistance through contact region geometry (horizontal dimension). The asymmetric perimeter lengths of the contact regions provide a planar solution that compensates for high sheet resistance without requiring changes to the semiconductor layer thickness or material properties.
Data Source
AI summary
The present invention provides a nitride semiconductor light-emitting element that can suppress current concentration without increasing drive voltage and manufacturing steps. A nitride semiconductor light-emitting element includes n-type electrodes arranged so that contact interfaces with a first nitride semiconductor layer are first contact regions extending in a first direction and p-type electrodes arranged so that contact interfaces with a second nitride semiconductor layer are second contact regions extending in the first direction, lengths of line segments of perimeter lines of the first contact regions parallel to the first direction being shorter than lengths of line segments of perimeter lines of the second contact regions parallel to the first direction and facing the first contact regions.