Surface-Emitting Laser DBR Structure With Transparent Conductive Layer
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Solution Overview
Problem
Existing surface-emitting lasers face challenges in reducing diffraction loss, improving heat dissipation, increasing yield, and enhancing reliability, as previous techniques have not adequately addressed these issues.
Innovation Solution
The development of a surface-emitting laser with a vertical resonator structure that includes a transparent conductive layer made of materials like ITO, ZnO, or IGZO, integrated into the DBR mirror layers, which reduces diffraction loss and improves heat dissipation by forming an intracavity structure that does not rely on current flow through the bonding interface, thereby enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional DBR mirror layers are used in surface-emitting lasers, then the laser structure is simple, but diffraction loss is high and heat dissipation is poor
Solution Approach 1:
The patent applies composite materials by integrating transparent conductive oxide layers (ITO, ZnO, IGZO) with traditional dielectric materials (TiO2, SiO2) in the DBR mirror structure. This composite approach reduces diffraction loss by providing both optical functionality and electrical conductivity, while the transparent conductive layer serves multiple functions simultaneously, resolving the contradiction between energy loss reduction and structural complexity.
Solution Approach 2:
The transparent conductive oxide layer performs multiple functions: it acts as part of the DBR mirror structure for optical reflection, provides electrical conductivity for current injection, and enables heat dissipation pathways. This multi-functionality reduces diffraction loss without proportionally increasing structural complexity, as one layer accomplishes what would traditionally require multiple separate components.
2Temperature
If conventional DBR mirror layers are used in surface-emitting lasers, then the manufacturing process is simple, but heat dissipation is insufficient
Solution Approach 1:
The patent integrates transparent conductive oxide materials with dielectric materials in the DBR structure. The transparent conductive oxide layers provide enhanced thermal conductivity compared to traditional dielectric-only structures, improving heat dissipation. The manufacturing process incorporates these materials using standard sputtering or atomic layer deposition techniques, so while the material composition becomes more complex, the fabrication processes remain compatible with existing semiconductor manufacturing capabilities.
3Reliability
If bonding interface current flow is used, then the laser structure is simple, but reliability is poor
Solution Approach 1:
The patent extracts the current flow path from the bonding interface by implementing an intracavity current injection structure. The transparent conductive oxide layer within the cavity provides a dedicated current pathway that bypasses the bonding interface, removing the reliability issue from the bonding junction. This extraction of current flow from the bonding interface improves reliability without significantly increasing overall device complexity, as the current path is integrated into the existing cavity structure.
4Productivity
If traditional surface-emitting laser structures are used, then the device is easy to manufacture, but yield is low
Solution Approach 1:
The patent uses composite materials comprising transparent conductive oxides and dielectric materials in the DBR structure. This composite approach improves manufacturing yield by providing more robust optical and electrical performance that is less sensitive to fabrication variations. The transparent conductive oxide layers can be deposited using scalable techniques like sputtering, and their properties are more controllable and repeatable across production batches, leading to higher yields despite the slightly more complex material stack.
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 results in reduced diffraction loss, improved heat dissipation, increased yield, and improved reliability, while also allowing for independent driving of the laser and easier integration with Si photonics, making it suitable for applications like TOF modules and packages.
Implementation Method 1
the transparent conductive layer may be transparent to an emission wavelength, and may transmits light of a predetermined emission wavelength or of a predetermined emission wavelength band
Implementation Method 2
a vertical resonator structure formed on the substrate, in which the vertical resonator structure includes at least one element selected from a group consisting of In, Ga, Al, N, As, and P, and includes at least an active layer, an upper DBR layer, and a lower DBR layer
Implementation Method 3
the upper DBR layer and the lower DBR layer are formed with the active layer interposed therebetween
Data Source
AI summary
To provide a surface-emitting laser that can achieve further reduction of diffraction loss, further improvement of heat dissipation, further improvement of yield, and further improvement of reliability.To provide a surface-emitting laser including a substrate and a vertical resonator structure formed on the substrate, in which the vertical resonator structure includes at least one element selected from the group consisting of In, Ga, Al, N, As, and P, and includes at least an active layer, an upper DBR layer, a lower DBR layer, the upper DBR layer and the lower DBR layer are formed with the active layer interposed therebetween, and the lower DBR layer includes at least one transparent conductive layer that contains a transparent conductive material including a non III-V semiconductor.