AlGaN UV LED Layer Composition Gradient for Vertical Substrate Separation
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Solution Overview
Problem
Current ultraviolet light emitting devices face challenges in achieving vertical realization and maintaining crystallinity during the substrate separation process, leading to reduced optical output power and efficiency.
Innovation Solution
A semiconductor device structure is designed with a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer, where the second conductive semiconductor layer includes a 2-2 layer with higher aluminum composition and a 2-1 layer with lower aluminum composition, optimized to enhance light emission and reduce absorption, along with specific thickness and composition gradients to improve crystallinity and optical output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional ultraviolet light emitting device structure is used, then the device can be manufactured with standard processes, but the crystallinity decreases during substrate separation and vertical realization becomes difficult
Solution Approach 1:
The device is divided into distinct functional layers including a first conductive semiconductor layer, an active layer with multiple quantum wells, and a second conductive semiconductor layer. This segmentation allows each layer to be optimized independently for its specific function while maintaining overall device integrity during substrate separation
Solution Approach 2:
Different regions of the semiconductor structure have different aluminum compositions optimized for their specific functions. The barrier layers have higher aluminum composition (30-70%) for better hole blocking, while the well layers have lower aluminum composition (10-50%) for efficient light emission, resolving the contradiction between manufacturing ease and crystallinity
2Reliability
If the aluminum composition is increased to improve hole blocking capability, then carrier confinement improves, but light absorption increases reducing optical output power
Solution Approach 1:
The aluminum composition is locally optimized in different layers: barrier layers have higher aluminum content (30-70%) for effective hole blocking and carrier confinement, while well layers have lower aluminum content (10-50%) to minimize light absorption and maximize optical output power
Solution Approach 2:
The aluminum composition parameter is varied across different layers and even within layers to achieve optimal performance. By changing the aluminum composition gradient, the device achieves both effective carrier confinement and minimal light absorption losses
3Ease of manufacture
If a simple layer structure is used, then manufacturing is easier, but optical output power and efficiency are reduced
Solution Approach 1:
The active region is segmented into multiple quantum well layers separated by barrier layers, creating a multi-layer structure that enhances carrier confinement and recombination efficiency, thereby increasing optical output power while remaining manufacturable
Solution Approach 2:
The device uses composite AlGaN structures with varying aluminum compositions in different layers. This composite approach combines the advantages of high aluminum content layers for carrier blocking and low aluminum content layers for efficient light emission, achieving high optical output power
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
The structure enables the production of a vertical ultraviolet light emitting device with enhanced optical output power by minimizing light absorption and maintaining high crystallinity, thereby improving the device's efficiency and performance.
Implementation Method 1
an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer. The active layer may include a plurality of barrier layers and a plurality of well layers
Implementation Method 2
The barrier layers, the well layers, the 2-2 conductive semiconductor layer, and the 2-1 conductive semiconductor layer may include AlGaN. The 2-2 conductive semiconductor layer may have a higher aluminum composition than the well layers, and the 2-1 conductive semiconductor layer may have a lower aluminum composition than the well layers
Data Source
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AI summary
Disclosed are a semiconductor device including a semiconductor structure including a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer, and a semiconductor device package including the semiconductor device. The active layer includes a plurality of barrier layers and a plurality of well layers. The second conductive semiconductor layer includes a 2-2 conductive semiconductor layer and a 2-1 conductive semiconductor layer disposed on the 2-2 conductive semiconductor layer. The barrier layers, the well layers, the 2-2 conductive semiconductor layer, and the 2-1 conductive semiconductor layer include AlGaN. The 2-2 conductive semiconductor layer has a higher aluminum composition than the well layers, and the 2-1 conductive semiconductor layer has a lower aluminum composition than the well layers. The aluminum composition of the 2-1 conductive semiconductor layer decreases with a first slope as the 2-1 conductive semiconductor layer is further away from the active layer, and the aluminum composition of the 2-2 conductive semiconductor layer decreases with a second slope as the 2-2 conductive semiconductor layer is further away from the active layer, wherein the first slope is greater than the second slope.