Semiconductor Laser Window Region Zn Diffusion Control
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Solution Overview
Problem
Current semiconductor laser devices face challenges in forming effective window regions in both infrared and red laser active layers within a single Zn diffusion step, leading to issues like excessive Zn diffusion, crystal quality deterioration, and electrical short circuits, which hinder high power operation and increase fabrication costs.
Innovation Solution
The semiconductor laser device incorporates a first and second light emitting device with adjusted lattice constants for their respective cladding layers to compensate for the difference in Zn diffusion rates between the infrared and red laser active layers, allowing a proper amount of Zn to be diffused in a single step, forming excellent window regions and preventing optical damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single Zn diffusion step is used to form window regions in both infrared and red laser active layers, then fabrication process is simplified, but Zn diffusion rate difference causes excessive diffusion in one layer and insufficient diffusion in the other
Solution Approach 1:
The patent applies local quality by making the cladding layers have different lattice constants tailored to their respective active layers. The first cladding layer has a lattice constant matched to the infrared active layer, while the second cladding layer has a lattice constant matched to the red active layer. This local customization of lattice constants allows each region to control Zn diffusion at the appropriate rate, resolving the contradiction between process simplicity and diffusion precision.
2Reliability
If Zn diffusion is increased to ensure sufficient window region formation in the infrared active layer, then window region quality improves, but excessive Zn diffusion occurs in the red active layer causing crystal quality deterioration
Solution Approach 1:
The patent implements local quality by assigning different lattice constants to different cladding layers. The first cladding layer (with lattice constant closer to GaAs) allows sufficient Zn diffusion into the infrared active layer, while the second cladding layer (with lattice constant closer to AlGaInP) restricts Zn diffusion into the red active layer. This localized differentiation resolves the contradiction between ensuring sufficient window region formation and preventing crystal quality deterioration.
3Reliability
If Zn diffusion is increased to ensure sufficient window region formation in the red active layer, then window region quality improves, but excessive Zn diffusion occurs in the infrared active layer causing electrical short circuits
Solution Approach 1:
The patent applies local quality by making the second cladding layer have a lattice constant that is closer to the red active layer than to the infrared active layer. This creates a diffusion barrier effect that restricts Zn diffusion into the red active layer while allowing sufficient diffusion into the infrared active layer. The localized lattice constant differentiation prevents harmful excessive Zn diffusion that would cause electrical short circuits.
4Manufacturing precision
If separate Zn diffusion steps are used for infrared and red laser active layers, then Zn diffusion control precision improves, but fabrication process complexity and cost increase
Solution Approach 1:
The patent merges the Zn diffusion process for both infrared and red laser active layers into a single simultaneous diffusion step. By designing the cladding layers with different lattice constants, the patent achieves precise control of Zn diffusion for both layers without requiring separate diffusion steps. This merging approach resolves the contradiction between diffusion precision and process complexity.
5Manufacturing precision
If lattice constants of cladding layers are adjusted to compensate for Zn diffusion rate differences, then Zn distribution uniformity improves, but fabrication process complexity increases
Solution Approach 1:
The patent applies parameter changes by adjusting the lattice constants of the cladding layers as the key parameter to control Zn diffusion rates. By changing the lattice constant parameter of each cladding layer to match its corresponding active layer, the patent achieves uniform Zn distribution in both layers. This parameter-based approach provides a straightforward solution that balances precision improvement with acceptable structural complexity.
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
This approach enables high output power operation by preventing optical damage and improving yield and reducing fabrication costs, while ensuring proper Zn distribution in both active layers without excessive diffusion or electrical short circuits.
Implementation Method 1
Then, Zn contained in the ZnO film is diffused by annealing so as to reach lower part of the ZnO film in the active layer.
Data Source
AI summary
A semiconductor laser device includes: a first light emitting device, the first light emitting device including a first first-conductive-type cladding layer, a first active layer having a first window region in the vicinity of a light emitting edge surface and a first second-conductive-type cladding layer stacked in this order on a substrate; and a second light emitting device, the second light emitting device including a second first-conductive-type cladding layer, a second active layer having a second window region in the vicinity of a light emitting edge surface and a second second-conductive-type cladding layer stacked in this order on the substrate. In the semiconductor laser device, respective lattice constants of the first second-conductive-type and second second-conductive-type cladding layers are adjusted to compensate for a difference in diffusion rate of an impurity between the first window region in the first active layer and the second window region in the second active layer.