Surface Emitting Optical Semiconductor Device Current Confinement
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Solution Overview
Problem
Conventional surface emitting type optical semiconductor devices face challenges in achieving high optical output due to low current confinement efficiency and increased device resistance, leading to heat generation and unstable optical mode, particularly when operating at high frequencies or with increased transmission rates.
Innovation Solution
The design incorporates a surface emitting type optical semiconductor device with a substrate, reflecting mirror layers, and a semiconductor active layer, featuring current confinement regions separated by an impurity region and a semiconductor current diffusion layer with a stacked structure to ensure uniform current injection and reduced resistance, allowing for increased optical output while maintaining stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the diameter of the current confinement portion is reduced to obtain high optical stability in the lateral mode, then the optical stability is improved, but the optical output is restricted from increasing
Solution Approach 1:
The current confinement structure is divided into multiple current confinement portions separated by high resistance regions formed through ion implantation. This segmentation allows each portion to maintain stable lateral mode while the collective structure provides sufficient current confinement area for high optical output.
2Productivity
If the injection current density is increased to raise the optical output in a small device size, then the optical output is improved, but heat generation increases and device characteristics are degraded
Solution Approach 1:
The current confinement structure is divided into multiple current confinement portions separated by high resistance regions formed through ion implantation. This segmentation allows each portion to maintain stable lateral mode while the collective structure provides sufficient current confinement area for high optical output.
3Reliability
If the contact area is increased to reduce contact resistance, then the contact resistance is improved, but the aperture of the laser emission port must be increased which control the lateral mode becomes difficult
Solution Approach 1:
The current confinement structure is divided into multiple current confinement portions separated by high resistance regions formed through ion implantation. This segmentation allows each portion to maintain stable lateral mode while the collective structure provides sufficient current confinement area for high optical output.
Solution Approach 2:
High resistance regions are selectively formed in specific areas through ion implantation to provide current confinement, while other areas maintain low resistance for good electrical contact. This local differentiation of electrical properties allows simultaneous optimization of contact resistance and lateral mode control.
4Productivity
If multiple current confinement portions are provided to increase optical output, then the optical output is improved, but the device resistance increases making uniform current injection difficult
Solution Approach 1:
A semiconductor current diffusion layer is introduced as an intermediary between the multiple current confinement portions and the electrode. This diffusion layer provides a low resistance path for current distribution, enabling uniform current injection across all current confinement portions while maintaining high optical output.
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 configuration enables uniform current injection and reduced device resistance, enhancing optical output and stability, even at high frequencies, by effectively managing heat generation and maintaining stable optical modes.
Implementation Method 1
an impurity region having impurities, the current confinement regions being separated by the impurity region
Implementation Method 2
a semiconductor current diffusion layer provided on the second reflecting mirror layer so as to cover the current confinement regions
Data Source
AI summary
It makes possible to inject a current into the current confinement region substantially uniformly. A surface emitting type optical semiconductor device includes a semiconductor active layer provided above a substrate; a first and second reflecting mirror layers sandwiching the semiconductor active layer to form an optical cavity in a direction perpendicular to the substrate; a plurality of current confinement regions provided in the second reflecting mirror layer so as to be separated by an impurity region having impurities; a semiconductor current diffusion layer provided on the second reflecting mirror layer so as to cover the current confinement regions; and an electrode portion which injects a current into the semiconductor active layer. The electrode portion comprising a first electrode provided on the semiconductor current diffusion layer so as to surround the current confinement regions and a second electrode provided on an opposite side of the substrate from the semiconductor active layer.