Deep-UV AlGaN Emitting Layer Structure for Electron Injection

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Solution Overview

Problem

The insertion of a photonic crystal structure between the n-type clad layer with a high AIN composition ratio and the active layer in semiconductor light-emitting elements for deep ultraviolet light emission affects electron injection efficiency, leading to poorer light emission characteristics.

Innovation Solution

Incorporating a planarization layer with a low AIN composition ratio between the n-type clad layer and the well layer, configuring the conduction band ground level of the planarization layer to be higher than that of the well layer to inhibit light emission in the planarization layer and enhance the flatness and emission characteristics of the well layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a photonic crystal structure is inserted between the n-type clad layer with high AIN composition ratio and the active layer, then the flatness of the active layer is enhanced, but the electron injection efficiency deteriorates and light emission characteristics worsen

Engineering Contradiction:
Improveflatness of active layerVSAvoidelectron injection efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent introduces an intermediate layer with lower AIN composition ratio between the high AIN composition ratio n-type clad layer and the active layer. This intermediate layer serves as a mediator that maintains the flatness benefit while reducing the harmful effect on electron injection efficiency, thereby resolving the technical contradiction between flatness enhancement and electron injection efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If AlGaN with high AIN composition ratio is used as the n-type clad layer, then deep ultraviolet light emission is enabled, but the flatness of the active layer deteriorates

Engineering Contradiction:
Improvedeep ultraviolet light emissionVSAvoidflatness of active layer
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent segments the n-type clad layer into multiple layers with different AIN composition ratios. The lower layer has high AIN composition ratio for deep ultraviolet light emission, while the upper intermediate layer has lower AIN composition ratio for providing flatness to the active layer. This segmentation allows simultaneous achievement of deep ultraviolet emission and active layer flatness.

Inventive Principle:
Principle #1Segmentation

3Object-generated harmful factors

If the ground level of the conduction band of the planarization layer is configured to be higher than that of the well layer, then light emission in the planarization layer is inhibited, but the full width at half maximum of the emission spectrum increases

Engineering Contradiction:
Improvelight emission in planarization layerVSAvoidfull width at half maximum of emission spectrum
Core Design Contradiction:
Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The patent optimizes the energy band parameters of the planarization layer by adjusting its thickness and AIN composition ratio. By configuring the ground level of the conduction band to be higher than that of the well layer through precise parameter control, the patent suppresses light emission in the planarization layer while minimizing the increase in full width at half maximum of the emission spectrum.

Inventive Principle:
Principle #35Parameter changes

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

This approach improves the light emission characteristics of semiconductor light-emitting elements by reducing the full width at half maximum of the emission spectrum and enhancing monochromaticity without impairing emission intensity.

Implementation Method 1

By configuring the ground level of the conduction band of the planarization layer to be higher than that of the well layer, light emission in the planarization layer is inhibited and light emission in the highly flat well layer is induced

Methodology Applied
Scientific EffectEnergy band alignment:

Data Source

PatentEP3595021B1Semiconductor light-emitting element and method for manufacturing semiconductor light-emitting element
Publication Date: 2024.07.24 NIKKISO CO LTD
  • EP3595021B1 patent drawingFigure 1~2
  • EP3595021B1 patent drawingFigure 3

AI summary

A semiconductor light-emitting element 10 includes: an n-type clad layer 24 of an n-type AlGaN-based semiconductor material; an active layer 26 including a planarizing layer (first planarizing layer 41) of an AlGaN-based semiconductor material provided on the n-type clad layer 24, a barrier layer (first barrier layer 40a) of an AlGaN-based semiconductor material provided on the planarizing layer, and a well layer 36 of an AlGaN-based semiconductor material provided on the barrier layer; and a p-type semiconductor layer provided on the active layer 26. The active layer 26 emits deep ultraviolet light having a wavelength of 360 nm or shorter, and a ground level of a conduction band of the planarizing layer (first planarizing layer 41) is lower than a ground level of a conduction band of the barrier layer (first barrier layer 40a) and higher than a ground level of a conduction band of the well layer 36.