AlGaInP Laser AR Coating Structure for Low Reflectance Stability
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Solution Overview
Problem
Existing external resonator type semiconductor lasers face challenges in achieving long-term reliability and low reflectance due to the chemical instability of AlGaInP-based materials, particularly in the 600 nm to 700 nm band, where precise film thickness control is required for antireflection coatings, and oxidation and moisture ingress are significant issues.
Innovation Solution
A semiconductor light-emitting element with a multilayer AR film structure is developed, comprising a first layer of Al2O3 with a higher rare gas element content for crystal protection and a second layer with minimal rare gas element content for reflectance adjustment, ensuring a dense film formation that prevents oxidation and moisture ingress, thereby maintaining low reflectance and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single-layer Al2O3 AR film is formed on AlGaInP-based semiconductor material, then reflectance can be reduced, but the film is susceptible to oxidation and moisture ingress, degrading long-term reliability
Solution Approach 1:
The patent applies composite materials by forming a multilayer AR film structure consisting of an Al2O3 layer and a rare gas element-containing layer. This composite structure combines the low reflectance properties of Al2O3 with the protective properties of the rare gas element-containing layer, which prevents oxidation and moisture ingress. The Al2O3 layer provides the antireflection function while the rare gas element-containing layer acts as a protective barrier, thereby achieving both low reflectance and long-term reliability simultaneously.
2Loss of energy
If film thickness is precisely controlled to achieve low reflectance, then reflectance can be reduced to 0.1% or less, but the manufacturing process becomes extremely difficult and costly
Solution Approach 1:
The patent applies parameter changes by introducing rare gas elements (such as neon, argon, krypton, or xenon) into the Al2O3 film during the film formation process. This changes the physical and chemical parameters of the film, creating a dense structure with improved protective properties. By adjusting the rare gas element content and film formation conditions, the patent achieves both low reflectance and high reliability without requiring extremely precise film thickness control, thereby simplifying the manufacturing process.
3Illumination intensity
If AlGaInP-based material is used for 600 nm to 700 nm band lasers, then the desired wavelength range can be achieved, but the material is chemically unstable and weak against oxidation
Solution Approach 1:
The patent applies the intermediary principle by introducing a rare gas element-containing layer as a protective intermediary between the AlGaInP-based semiconductor material and the external environment. This intermediate layer acts as a barrier that prevents oxidation and moisture ingress, protecting the chemically unstable AlGaInP material. The rare gas element-containing layer serves as a mediator that allows the AlGaInP material to maintain its desired optical properties (600 nm to 700 nm wavelength range) while improving its chemical stability and long-term reliability.
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 multilayer AR film structure achieves long-term reliability and low reflectance, effectively suppressing moisture permeation and reflectance fluctuations, ensuring stable operation of the semiconductor laser.
Implementation Method 1
an anti-reflection (AR) film including a first layer containing Al2O3 formed on an emission side end surface of the epitaxial layered structure, and a second layer formed on the first layer
Implementation Method 2
antireflection film (AR) coating is applied to adjust reflectance of an emission side end surface of the semiconductor laser element
Data Source
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AI summary
A semiconductor light-emitting element including an AR film having long-term reliability and low reflectance is provided. A semiconductor light-emitting element 100 includes: a semiconductor substrate 110, an epitaxial layered structure 120 made of an AIGalnP-based material, and an anti-reflection (AR) film 160. The AR film 160 includes a first layer 162 containing Al2O3 formed on an emission side end surface S1 of the epitaxial layered structure 120, and a second layer 164 formed on the first layer 162. A rare gas element content in the first layer 162 is larger than a rare gas element content in the second layer 164.