Semiconductor Light Emitting Device Electrode Width Variation
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Solution Overview
Problem
Conventional semiconductor light emitting devices with face-up type electrode arrangements suffer from non-uniform current density distribution, leading to non-uniform light emission distribution, which affects their performance and efficiency.
Innovation Solution
The design incorporates a first electrode with a width-increasing portion and a second electrode with strategically positioned extending portions to deconcentrate current density, ensuring uniform light emission distribution by optimizing the arrangement and shape of the electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a face-up type electrode arrangement is used, then ease of mounting onto a package is improved, but current density distribution uniformity deteriorates
Solution Approach 1:
The patent applies local quality by creating different electrode shapes with specific width variations at different locations. The first electrode has a wider width at its distal end compared to its proximal end, while the second electrode has a narrower width at its distal end compared to its proximal end. This non-uniform width distribution across different electrode regions optimizes current density uniformity while maintaining the face-up type arrangement for ease of mounting.
2Device complexity
If conventional electrode shapes are used, then device complexity is reduced, but light emission distribution uniformity deteriorates
Solution Approach 1:
The patent introduces local quality variations in electrode geometry to achieve uniform light emission. The first electrode features a width-increasing portion at its distal end, and the second electrode has a width-decreasing portion at its distal end. These localized geometric modifications optimize current distribution and light emission uniformity without substantially increasing overall device complexity.
3Manufacturing precision
If electrode widths are uniform, then manufacturing precision is improved, but current density uniformity deteriorates
Solution Approach 1:
The patent deliberately introduces non-uniform width characteristics at specific locations of the electrodes. The first electrode has a wider distal end portion compared to its proximal end, while the second electrode has a narrower distal end portion compared to its proximal end. This controlled local width variation compensates for current density non-uniformity that would otherwise occur in uniform-width electrodes.
Solution Approach 2:
The patent applies asymmetry by creating electrodes with non-symmetric width profiles. The first electrode is asymmetric with its distal end being wider than its proximal end, and the second electrode is asymmetric with its distal end being narrower than its proximal end. This asymmetric design optimizes current distribution patterns to achieve more uniform current density across the device.
Data Source
AI summary
According to one embodiment, a semiconductor light emitting device includes a stacked structural body, a first electrode, and a second electrode. The stacked structural body includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a light emitting portion. The stacked structural body has a first major surface on a side of the second semiconductor layer. The first electrode is provided on the first semiconductor. The second electrode is provided on the second semiconductor layer. The first electrode includes a first pad portion and a first extending portion that extends from the first pad portion along a first extending direction. The first extending portion includes a first width-increasing portion. A width of the first width-increasing portion along a direction orthogonal to the first extending direction is increased from the first pad portion toward an end of the first extending portion.