Deep-UV III Nitride Epitaxial Structure With Compressive-Strain Template
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
III nitride light-emitting semiconductor devices, particularly for deep ultraviolet wavelengths, face challenges in achieving high emission power due to compressive strain and material differences between blue and UV light-emitting devices, with existing templates not effectively supporting compressively-strained active layers for enhanced emission intensity.
Innovation Solution
A III nitride light-emitting device is developed with a template layer of AlXGa1-XN having compressive strain, an active layer with compressively-strained AlGaN, and n-type III nitride semiconductor regions to enhance deep ultraviolet emission, utilizing a template substrate with a principal surface of a material different from III nitride and incorporating specific growth conditions for the n-type semiconductor layers to maintain lattice relaxation and surface roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an AlN template layer is used as underlying semiconductor for UV light-emitting devices, then the material compatibility for deep UV emission is improved, but the n-type semiconductor layers require changing from GaN to AlN or AlGaN of higher Al molar fractions which increases lattice mismatch and reduces emission intensity
Solution Approach 1:
The patent applies parameter changes by systematically varying the Al molar fraction in the template layer and n-type semiconductor layers. The template layer uses AlN (X=1.0) while the n-type layers use AlGaN with controlled Al content (0.7≤x≤1.0), creating a gradient that balances deep UV emission capability with lattice matching to reduce dislocation density and improve emission intensity
Solution Approach 2:
The patent employs composite material structure by combining AlN template layer with AlGaN n-type semiconductor layers of varying composition. This composite approach allows the template layer to provide deep UV emission capability while the AlGaN layers provide better lattice matching and electrical properties, achieving both goals simultaneously
2Manufacturing precision
If the Al molar fraction is increased in n-type semiconductor layers to maintain lattice matching with AlN template, then lattice relaxation is reduced, but the emission intensity in deep ultraviolet wavelengths decreases
Solution Approach 1:
The patent applies local quality by differentiating the Al molar fraction in different regions: the template layer has high Al content (AlN, X=1.0) for lattice matching and structural stability, while the n-type semiconductor layers have controlled Al content (0.7≤x≤1.0) optimized for electrical performance and emission. This spatial variation in composition allows simultaneous optimization of lattice matching and emission intensity
3Illumination intensity
If compressive strain is applied to the active layer to enhance emission intensity, then the emission power increases, but the device complexity increases due to additional template layer and strain control requirements
Solution Approach 1:
The patent applies preliminary action by pre-establishing the compressive strain in the template layer and n-type semiconductor layers before the active layer is formed. The template layer and underlying n-type layers are designed with specific Al molar fractions and thicknesses that create the desired compressive strain state, which is then transferred to the active layer during growth, eliminating the need for post-growth strain adjustment
Solution Approach 2:
The patent uses the n-type semiconductor layers as an intermediary between the AlN template layer and the active layer. These intermediate layers serve dual functions: they provide the compressive strain necessary for enhanced emission while also serving as the electrical contact and transport path, thereby simplifying the overall device structure by combining multiple functions in a single layer system
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 provides a III nitride light-emitting device with improved emission intensity in deep ultraviolet wavelengths by effectively applying compressive strain to the active layer, increasing the emission power and reducing lattice relaxation, thereby enhancing the device's performance.
Implementation Method 1
the template layer including compressive strain, the template layer including an AlXGa1-XN
Implementation Method 2
maintain lattice relaxation and surface roughness
Implementation Method 3
the n-type second III nitride semiconductor layer having a surface roughness of 0.4 nm or less
Implementation Method 4
an active layer disposed on the template member so as to generate light having a peak wavelength in deep ultraviolet wavelengths 285 nm or below
Data Source
AI summary
A III nitride light-emitting device comprises: a template member having a template layer that includes compressive strain and covers the principal surface including AlXGa1-XN that has a full width at half maximum of a (10-12)-face X-ray rocking curve with 1000 arcsec or lower, where X is greater than zero and 1 or less; an active layer including a compressively strained AlGaN and generating light having a peak wavelength in deep ultraviolet wavelengths of 285 nm or below; and an n-type III nitride semiconductor region disposed on the template member. The n-type III nitride semiconductor region has an n-type first and second III nitride semiconductor layers on the template member. The n-type first III nitride semiconductor layer has a lattice relaxation rate of 2% or less relative to that of the template layer, and the n-type second III nitride semiconductor layer has a surface roughness of 0.4 nm or less.