Quantum Cascade Laser and Detector Monolithic Integration
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Solution Overview
Problem
Optimizing the characteristics of both quantum cascade lasers and detectors in a monolithic optical semiconductor element is challenging due to their shared layer structure, which limits their individual performance and design flexibility.
Innovation Solution
The optical semiconductor element features a first and second laminated structure on a semiconductor substrate, where the second laminated structure includes a dummy region with the same layer structure as the first, allowing the quantum cascade laser and detector to be positioned at different heights, enabling independent optimization of their characteristics and facilitating heat radiation and voltage application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the quantum cascade laser and quantum cascade detector are formed with the same layer structure through monolithic fabrication, then positional accuracy between the two components is very high, but it becomes difficult to optimize characteristics of each component independently
Solution Approach 1:
The patent introduces a vertical dimension by positioning the quantum cascade laser and quantum cascade detector at different heights from the front surface of the semiconductor substrate. The quantum cascade laser is positioned at a first height while the quantum cascade detector is positioned at a second height that is different from the first height. This vertical separation allows independent optimization of each component's characteristics while maintaining high positional accuracy through monolithic fabrication, as the different heights enable different layer structures and contact layer configurations for each component.
2Adaptability or versatility
If the quantum cascade laser and quantum cascade detector are positioned at different heights from the front surface, then independent optimization of characteristics is achieved, but the device structure becomes more complex
Solution Approach 1:
The patent segments the semiconductor device into distinct vertical zones by positioning the quantum cascade laser and quantum cascade detector at different heights. This segmentation allows each component to have its own optimized layer structure and contact layer configuration. The quantum cascade laser has its active layer electrically connected to a first contact layer and the semiconductor substrate, while the quantum cascade detector has its active layer electrically connected to a second contact layer and a third contact layer corresponding to the first contact layer in the dummy region. This segmentation enables independent characteristics optimization while maintaining a unified monolithic structure.
Solution Approach 2:
The patent employs a dummy region that replicates the layer structure of the quantum cascade laser region. The dummy region includes a third contact layer corresponding to the first contact layer, allowing the quantum cascade detector to be positioned at a different height with its own contact layer configuration. This copying approach enables independent optimization of each component while maintaining structural consistency and facilitating manufacturing through standard semiconductor processes.
3Temperature
If the quantum cascade laser is positioned to enhance heat radiation via the semiconductor substrate, then thermal management is improved, but the positioning flexibility is reduced
Solution Approach 1:
The patent resolves this contradiction by utilizing the vertical dimension. The quantum cascade laser is positioned at a specific first height from the front surface of the semiconductor substrate, which is optimized for heat radiation through the substrate. The quantum cascade detector is positioned at a different second height. This vertical positioning strategy allows the laser to have optimal thermal contact with the substrate for heat dissipation while the detector can be positioned independently for optimal optical and electrical characteristics, thus maintaining positioning flexibility through the vertical dimension.
Data Source
AI summary
An optical semiconductor element includes a semiconductor substrate, a first laminated structure provided on a front surface of the semiconductor substrate, and a second laminated structure provided on the front surface of the semiconductor substrate, the first laminated structure includes a first quantum cascade region, the second laminated structure includes a dummy region having the same layer structure as the first quantum cascade region, a second quantum cascade region provided on the front surface of the semiconductor substrate via the dummy region, and one of the first quantum cascade region and the second quantum cascade region is a quantum cascade laser, and the other of the first quantum cascade region and the second quantum cascade region is a quantum cascade detector.