Semiconductor Layer Stack for Stress-Buffered Light Confinement
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Solution Overview
Problem
Existing light-emitting devices, such as edge-emitting laser diodes, suffer from stress and strain accumulation in guide and cladding layers due to mismatched lattice constants, leading to defects and surface irregularities.
Innovation Solution
A light-emitting device design incorporating a stack structure with alternating indium-containing semiconductor layers and aluminum-containing semiconductor layers, acting as stress buffer layers, to mitigate stress and strain, thereby reducing surface defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of guide layer and cladding layer is increased to achieve light confining effect, then light confinement is improved, but stress and strain accumulation causes defects in the layers
Solution Approach 1:
The patent divides the thick guide layer and cladding layer into multiple thinner sub-layers with alternating compositions (InGaN/GaN or AlInGaN/GaN). This segmentation reduces the continuous stress accumulation that would occur in a single thick layer, while still achieving the required optical confinement through the cumulative effect of multiple interfaces.
Solution Approach 2:
The patent employs composite layer structures combining different semiconductor materials (InGaN, AlInGaN, GaN) with distinct lattice constants and optical properties. This composite approach allows optimization of both mechanical stress distribution and optical confinement, as each material layer contributes differently to the overall performance.
2Reliability
If alternating indium-containing and aluminum-containing semiconductor layers are introduced as stress buffer layers, then stress and strain are reduced, but device structure becomes more complex
Solution Approach 1:
The patent applies local quality by introducing specific buffer layers (InGaN or AlInGaN) only at critical interfaces where stress accumulation is most severe, rather than uniformly throughout the entire structure. The indium-containing layers provide tensile stress compensation while aluminum-containing layers provide compressive stress compensation, tailored to local requirements.
Solution Approach 2:
The patent utilizes parameter changes by varying the composition ratios (indium content x, aluminum content y) and thicknesses of buffer layers to precisely control stress states. By adjusting these parameters, the patent optimizes stress compensation while maintaining manufacturing feasibility and minimizing structural complexity.
Data Source
AI summary
A light-emitting device is provided. An active layer is disposed on a substrate and between the first semiconductor layer and the second semiconductor layer. The first aluminum-containing semiconductor layer is disposed between the substrate and the first semiconductor layer, and a first aluminum composition ratio of the first aluminum-containing semiconductor layer is greater than that of the first semiconductor layer. The second aluminum-containing semiconductor layer is disposed between the first aluminum-containing semiconductor layer and the first semiconductor layer, and a second aluminum composition ratio of the second aluminum-containing semiconductor layer is greater than that of the first semiconductor layer. The stack structure is disposed between the first and second aluminum-containing semiconductor layers, and the stack structure includes first, second, and third indium-containing semiconductor layers stacked in sequence. The first, second, and third indium-containing semiconductor layers are made of Ina1Alb1Ga1-a1-b1N (0<a1+b1<1), Ina2Alb2Ga1-a2-b2N (0<a2+b2<1, and Ina3Alb3Ga1-a3-b3N (0<a3+b3<1), respectively, and 0<a3≤a1<a2.