VCSEL Reflector Laminate for High Reflectivity and Heat Dissipation
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Solution Overview
Problem
Conventional vertical cavity surface-emitting lasers (VCSELs) face challenges in achieving high reflectivity and efficient heat dissipation due to the use of AlGaN as a low refractive index layer, which results in poor thermal conductivity and reduced productivity in manufacturing.
Innovation Solution
A reflector design incorporating a laminate structure of Ga-doped AlN and GaN layers as the low refractive index layer, combined with an InGaN layer as the high refractive index layer, which enhances reflectivity and thermal conductivity, allowing for strain compensation and improved heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If AlGaN is used as the low refractive index layer to achieve high reflectivity, then the reflectivity is improved, but the thermal conductivity deteriorates
Solution Approach 1:
The patent uses a composite low refractive index layer comprising alternating AlN layers and Ga-doped AlN layers. The AlN provides high reflectivity while the Ga-doped AlN layers improve thermal conductivity. This composite structure resolves the contradiction by combining materials with complementary properties to achieve both high reflectivity and adequate heat dissipation.
2Manufacturing precision
If temperature stabilization is required during layer growth to ensure quality, then the manufacturing precision is improved, but the productivity deteriorates
Solution Approach 1:
The patent employs Ga-doping in the AlN layers to modify the material properties, allowing the layers to be grown at a constant temperature without requiring temperature stabilization. The Ga-doping compensates for strain and enables high-quality layer growth at fixed temperature, thereby eliminating the time-consuming temperature stabilization process and improving productivity.
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 proposed reflector achieves high reflectivity exceeding 99.9% and improved heat dissipation, increasing the productivity and quality of surface-emitting lasers by allowing for the growth of layers at the same temperature without the need for temperature stabilization, thus reducing manufacturing time and enhancing light-emitting characteristics.
Implementation Method 1
a distributed bragg reflection (DBR) of the resonator needs a high reflectivity of 99% or more to repeatedly reflect light emitted from the light emitting layer and amplify the light
Implementation Method 2
The low refractive index layer includes a laminate of alternate Ga-doped AlN layers and layers consisting essentially of GaN
Data Source
AI summary
A reflector includes a low refractive index layer having a first average refractive index; and a high refractive index layer having a second average refractive index. The low refractive index layer includes a laminate of alternate Ga-doped AlN layers and layers consisting essentially of GaN. The high refractive index layer includes an InGaN layer. The second average refractive index is higher than the first average refractive index.