Vertical-cavity surface-emitting laser
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Solution Overview
Problem
Current vertical-cavity surface-emitting laser (VCSEL) manufacturing methods face challenges in reducing manufacturing complexity and preventing electrical disconnection and surface defects, which affect the reliability of the emitter.
Innovation Solution
The VCSEL design includes an insulation region formed by ion implantation, oxidation holes in the isolation region, and a specific structure for the ohmic contact layer with protrusions and via holes to ensure reliable current flow and prevent defects from affecting the emitter performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If etching is used to form a ring-shaped trench to concentrate current, then current concentration is improved, but manufacturing complexity increases
Solution Approach 1:
The patent extracts the current confinement function from the complex ring-shaped trench structure and relocates it to a simplified oxidation layer formed by selective oxidation of AlGaAs. This removes the need for etching deep trenches while maintaining current concentration in the aperture region.
Solution Approach 2:
The patent replaces the mechanical etching process with a chemical oxidation process. Instead of physically removing material to create trenches, an oxidation layer is grown selectively on AlGaAs regions, achieving current confinement through material property changes rather than structural removal.
2Manufacturing precision
If a ring-shaped trench is formed to concentrate current, then current concentration is improved, but electrical disconnection risk increases
Solution Approach 1:
The patent removes the trench structure that created disconnection risks and extracts the essential current confinement function to the oxidation layer. This eliminates the physical barrier that trenches created in the electrode path while preserving current concentration.
Solution Approach 2:
The patent designs the ohmic contact layer to extend under the oxidation layer, creating a redundant electrical pathway. This cushioning design ensures that even if the oxidation layer has defects, the electrical connection remains intact through the extended contact regions.
3Manufacturing precision
If a large area trench is formed around the emitter, then current concentration is improved, but emitter reliability deteriorates due to surface defects
Solution Approach 1:
The patent applies oxidation locally only to the AlGaAs regions surrounding the aperture, rather than forming a large trench around the entire emitter. This localized approach confines current effectively while minimizing the affected area and reducing the risk of surface defects impacting emitter performance.
Solution Approach 2:
The patent uses selective oxidation, a chemical process that grows an insulation layer in specific regions. This chemical approach is more precise and less invasive than mechanical trenching, concentrating current through material property changes in the oxidation layer without creating large structural disruptions.
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 design enhances the reliability of VCSELs by preventing electrical disconnection and surface defects, improving the overall performance and yield of the manufacturing process.
Implementation Method 1
an insulation region formed by ion implantation
Implementation Method 2
an aperture forming layer interposed between the upper mirror and the active layer, and including an oxidation layer and a window layer surrounded by the oxidation layer
Data Source
AI summary
A vertical-cavity surface-emitting laser (VCSEL) including a substrate including a plurality of emitters forming an array region, a lower mirror, an upper mirror, an active layer interposed between the lower mirror and the upper mirror, an aperture forming layer interposed between the upper mirror and the active layer and including an oxidation region and a window region, a connector disposed on the upper mirror, a plurality of oxidation holes passing through the upper mirror and the aperture forming layer, an upper insulation layer covering the plurality of oxidation holes, and a pad electrically connected to the connector, in which at least a portion of the connector is disposed in the plurality of oxidation holes, and the plurality of emitters is disposed in substantially a honeycomb shape on the substrate.