Pseudomorphic Quantum Well Structure for Semiconductor Light-Emitting Element
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Solution Overview
Problem
Semiconductor light-emitting elements with AlGaAs-based light emitting layers face issues with micro-crystal defects and stress-induced non-light emission centers, leading to reduced optical output due to the growth and spread of crystal defects, which degrade device reliability and efficiency, especially under high-temperature and high-humidity conditions.
Innovation Solution
Incorporating a pseudomorphic quantum well structure with Inx(Ga1-yAly)1-xAs well layers and Ga1-zAlzAs barrier layers, where 0<x≦0.2 and 0<y<1, alternately stacked, and controlling the In composition ratio to maintain crystallinity within the critical film thickness limits, suppresses the growth and spread of crystal defects, enhancing optical output and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light emitting layer is formed using AlGaAs or InGaAlP materials, then red to infrared light can be emitted, but micro-crystal defects and point defects in hetero-interfaces are introduced during manufacturing, which become non-light emission centers under stress and cause light absorption
Solution Approach 1:
The patent changes the compositional parameters of the light emitting layer by incorporating Inx(Ga1-yAly)1-xAs with specific composition ratios (0<x≤0.2, 0<y<1) to reduce lattice mismatch and minimize crystal defect formation during epitaxial growth, thereby improving manufacturing precision while maintaining optical output
Solution Approach 2:
The patent uses a composite material structure combining Inx(Ga1-yAly)1-xAs well layers with Ga1-zAlzAs barrier layers to create a pseudomorphic quantum well structure that suppresses crystal defect growth and spread, resolving the contradiction between achieving desired optical properties and minimizing manufacturing-induced defects
2Adaptability or versatility
If the device operates under high-temperature and high-humidity conditions, then the device can function in adverse environments, but crystal defects grow and spread, causing light absorption and reducing optical output
Solution Approach 1:
The patent designs the light emitting layer with predetermined compositional gradients and barrier structures that preemptively counteract the effects of thermal stress and humidity before crystal defects can grow and spread, cushioning against reliability degradation under adverse environmental conditions
Solution Approach 2:
The patent optimizes the compositional parameters (x, y, z ratios) of the Inx(Ga1-yAly)1-xAs and Ga1-zAlzAs layers to create a structure that is inherently more resistant to thermally-induced defect propagation, allowing the device to maintain optical output stability under high-temperature and high-humidity operation
3Illumination intensity
If the light emitting layer is made thicker to increase light emission, then optical output may improve, but crystal defects have more space to grow and spread, becoming more recombination centers
Solution Approach 1:
The patent creates a composite structure with alternating Inx(Ga1-yAly)1-xAs well layers and Ga1-zAlzAs barrier layers, where the barrier layers act as defect-blocking boundaries that prevent crystal defect propagation even as the overall structure thickness increases, allowing enhanced optical output without proportional increase in defect-related recombination
Solution Approach 2:
The patent segments the light emitting layer into multiple thin quantum well layers separated by barrier layers, which confines carriers and photons within each segment while preventing defect growth across the entire structure, thereby maintaining high optical output with suppressed defect propagation
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 pseudomorphic quantum well structure effectively suppresses crystal defect growth, maintaining optical output and reliability even under prolonged operation and adverse conditions, ensuring stable performance in optical coupling devices.
Implementation Method 1
Incorporating a pseudomorphic quantum well structure with Inx(Ga1-yAly)1-xAs well layers and Ga1-zAlzAs barrier layers, where 0<x≦0.2 and 0<y<1, alternately stacked, and controlling the In composition ratio to maintain crystallinity within the critical film thickness limits
Implementation Method 2
a fine point defect in a hetero-interface, which is introduced when executing an epitaxial growth
Implementation Method 3
The red light to the infrared light are emitted from a light emitting layer which is formed of AlGaAs, InGaAlP, or the like
Data Source
AI summary
A semiconductor light-emitting element includes a semiconductor stacked body that includes a light emitting layer in which n well layers (where n is, for example, an integer of 1 to 10) formed of Inx (Ga1-yAly)1-xAs (0<X≦0.2, 0<y<1), and (n+1) barrier layers formed of Ga1-zAlzAs (0<z<1) and are alternately stacked with the well layer. The light emitting layer in some embodiments can emit light having a peak wavelength in a range of from 700 nm or more to 870 nm or less.