VCSEL Transparent Conductive Layers Without Oxidation Defects
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Solution Overview
Problem
Existing vertical-cavity surface-emitting lasers face issues with oxidation layers formed by the oxidation process, which lead to defects, increased costs, and reduced light-emitting efficiency due to lattice mismatch and thermal expansion coefficient differences, affecting yield and reliability.
Innovation Solution
A vertical-cavity surface-emitting laser device with transparent conductive layers that eliminate the need for oxidation layers, utilizing transparent conductive layers and a novel structural design to enhance current transmission and reduce mesa size, allowing for improved light-emitting efficiency and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxidation process is used to form oxidation layer with high resistivity, then current limitation is achieved, but manufacturing cost increases and mesa size increases
Solution Approach 1:
The patent extracts and removes the oxidation layer from the device structure, replacing it with a transparent conductive layer that provides the necessary electrical properties without the harmful effects of oxidation-induced defects and lattice mismatch
Solution Approach 2:
The patent changes the electrical resistance parameter by using transparent conductive layers with optimized conductivity values, achieving the desired current limitation through structural design rather than through high-resistivity oxidation layers
2Reliability
If oxidation process is used to form oxidation layer with high resistivity, then current limitation is achieved, but mesa size increases
Solution Approach 1:
The patent removes the oxidation layer that necessitated large mesa dimensions, allowing for reduced mesa size while maintaining current limitation functionality through the transparent conductive layer design
Solution Approach 2:
The patent applies local quality by positioning transparent conductive layers specifically at critical regions where current control is needed, rather than requiring uniform current limitation across a large mesa area
3Reliability
If oxidation process is used, then high resistivity layer is formed, but light-emitting effect is influenced negatively
Solution Approach 1:
The patent extracts and removes the oxidation layer that negatively impacts light emission, replacing it with transparent conductive layers that are optically transparent and do not interfere with the light-emitting effect
Solution Approach 2:
The patent utilizes the optical transparency property of the transparent conductive layers, which allow light to pass through without the absorption and scattering effects caused by oxidation layers, thereby preserving and enhancing the light-emitting effect
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 improves the quality and light-emitting effect of the laser device by eliminating defects from the oxidation process, enabling smaller mesa sizes and concentrated light emission, while enhancing current flow and heat dissipation.
Implementation Method 1
The transparent conductive layers are respectively disposed on and correspond to the second reflective layers... the current passes through the transparent conductive layers
Implementation Method 2
The upper and lower Bragg reflectors form a vertical resonance cavity... the reflective portions are arranged on the base portion at intervals
Implementation Method 3
By applying a voltage, a current is poured into the active layer and excites the photons... the active light-emitting layers are respectively disposed on and correspond to the reflective portions
Data Source
AI summary
A vertical-cavity surface-emitting laser device having transparent conductive layers includes a substrate, a first reflective layer, a plurality of active light-emitting layers, a plurality of second reflective layers, and a plurality of transparent conductive layers. The first reflective layer is disposed on a top surface and includes a base portion and a plurality of reflective portions. The reflective portions are arranged on the base portion at intervals, and any two adjacent reflective portions are spaced apart by a distance. A plurality of exposed surfaces are defined on a region of the surface of the first reflective layer without the reflective portions. The active light-emitting layers are correspondingly and respectively disposed on the reflective portions. The second reflective layers are correspondingly and respectively disposed on the active light-emitting layers. The transparent conductive layers are correspondingly and respectively disposed on the second reflective layers.