Semiconductor Light Emitting Device With Segmented Clad Layer
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Solution Overview
Problem
Conventional ridge-type semiconductor lasers face challenges in reducing operating voltage while maintaining etching selectivity and ridge formation accuracy, leading to increased power consumption, temperature rise, and degraded reliability.
Innovation Solution
A semiconductor light emitting device with a laminated structure of at least three layers in the second conductive clad layer, where the Al compositions and film thicknesses satisfy specific relations, allowing for non-selective and selective etching to form a ridge with improved accuracy and reduced operating voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If Al composition in p-type AlGaInP clad layer is increased to secure etching selectivity, then ridge formation accuracy is improved, but operating voltage increases
Solution Approach 1:
The p-type AlGaInP clad layer is divided into multiple layers with different Al compositions. The first layer has lower Al composition (0.4-0.6) to reduce operating voltage, while the second layer has higher Al composition (0.6-0.8) to provide etching selectivity. This segmentation allows each layer to fulfill its specific function without compromising the other.
Solution Approach 2:
Different regions of the clad layer structure are assigned different Al compositions based on their functional requirements. The lower Al composition region optimizes for low operating voltage and reduced power consumption, while the higher Al composition region optimizes for etching selectivity and ridge formation accuracy. This local quality differentiation resolves the contradiction between these two opposing requirements.
2Use of energy by moving object
If Al composition in p-type AlGaInP clad layer is reduced to decrease operating voltage, then power consumption is reduced, but etching selectivity deteriorates
Solution Approach 1:
The clad layer structure is segmented into multiple layers where the first layer with lower Al composition reduces power consumption, and the second layer with higher Al composition maintains etching selectivity. This segmentation enables both objectives to be achieved simultaneously.
Solution Approach 2:
The clad layer structure uses a composite of multiple AlGaInP layers with different Al compositions. This composite structure combines the advantages of low-Al composition (low power consumption) and high-Al composition (high etching selectivity) materials, resolving the contradiction between power consumption and etching selectivity.
3Reliability
If high Al composition is used in ridge portion, then thermal saturation characteristic is improved, but operating voltage and power consumption increase
Solution Approach 1:
The higher Al composition is locally applied only in the second layer near the ridge portion to improve thermal saturation characteristic, while the first layer maintains lower Al composition to reduce overall power consumption. This local quality approach allows thermal performance improvement without excessive power consumption increase.
Solution Approach 2:
The clad layer is segmented into functional zones: the first layer with lower Al composition handles power consumption, while the second layer with higher Al composition handles thermal saturation characteristics. This segmentation enables independent optimization of both parameters.
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 solution achieves a semiconductor light emitting device with reduced operating voltage and improved ridge formation accuracy, maintaining equivalent current-optical output and far field pattern characteristics, thus reducing power consumption and enhancing long-term reliability.
Implementation Method 1
The etching rate is mainly adjusted by adjusting Al composition in each layer. Normally, if the Al composition is high, the etching rate becomes larger. If the Al composition is low, the etching rate becomes smaller.
Data Source
AI summary
A semiconductor light emitting device includes a first conductive clad layer that is group III-V semiconductor mixed crystal, an active layer, and a second conductive clad layer. The second conductive clad layer has a laminated structure of at least three layers including a first layer, a second layer, and a third layer disposed in this order closer to the active layer. The second layer and the third layer are included in a striped ridge, and the second layer is positioned at a skirt of the ridge. The surface of the first layer is a flat part at both sides of the ridge. When Al compositions of the first layer, second layer, and third layer are X1, X2, and X3, respectively, the relation X2>X1, X3 is satisfied. When film thicknesses of the first layer, second layer, and third layer are D1, D2, and D3, the relation D2<D3 is satisfied.