AlGaN Quantum Well LED Structure for Deep UV Recombination Efficiency

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Solution Overview

Problem

Deep UV LEDs face challenges due to high defect density and significant lattice mismatch in n-AlxGa1-xN ohmic contact layers, leading to reduced luminous efficiency.

Innovation Solution

The LED structure incorporates alternately stacked AlmGa1-mN barrier layers and AlnGa1-nN well layers with specific thickness ratios and compositions to enhance electron-hole recombination efficiency, including a constant or graded Al composition distribution to minimize defects and stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If n-AlxGa1-xN ohmic contact layer with high-aluminum-composition is used, then electrical conductivity is improved, but defect density increases and lattice mismatch worsens

Engineering Contradiction:

Improveelectrical conductivityVSAvoiddefect density and lattice mismatch

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by precisely controlling the aluminum composition ratio (x) in the n-AlxGa1-xN ohmic contact layer and optimizing the thickness ratio between well layers and barrier layers. This resolves the contradiction by finding optimal parameter values that achieve good electrical conductivity while minimizing defect density and lattice mismatch effects.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material structure by combining AlGaN well layers with AlN barrier layers in a multiple quantum well configuration. This composite structure allows the ohmic contact layer to achieve both good electrical conductivity and reduced defects by distributing the lattice mismatch stress across multiple interfaces rather than concentrating it in a single high-aluminum layer.

Inventive Principle:

Principle #40Composite materials

2Reliability

If AlN buffer layer is grown on sapphire substrate, then stress is reduced and internal quantum efficiency is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveinternal quantum efficiencyVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by growing the AlN buffer layer on the sapphire substrate before depositing the active region layers. This preliminary step pre-establishes a low-stress foundation that accommodates the lattice mismatch between sapphire and AlGaN, thereby reducing stress in subsequent layers and improving internal quantum efficiency without requiring complex in-situ stress management during active region growth.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If thickness ratio of well layer to barrier layer is optimized, then electron-hole recombination efficiency is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improveluminous efficiencyVSAvoidthickness control precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by establishing specific thickness ratio ranges (well layer to barrier layer between 1:3 to 1:8) that optimize electron-hole recombination efficiency. These parameter specifications provide clear manufacturing targets that balance luminous efficiency improvement with achievable manufacturing precision, avoiding overly stringent requirements while still achieving high performance.

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 configuration improves luminous efficiency and brightness by optimizing electron-hole recombination, ensuring consistent performance and extending the LED's lifespan.

Implementation Method 1

the active layer includes AlmGa1-mN barrier layers and AlnGa1-nN well layers, which are alternately stacked periodically... in at least one period of the multiple periods, a ratio of a thickness of the AlnGa1-nN well layer to a thickness of the AlmGa1-mN barrier layer is in a range of 1:3 to 1:8

Methodology Applied

Scientific EffectQuantum confinement effect:

Data Source

PatentUS20260090145A1Light emitting diode and light emitting device

Publication Date: 2026.03.26 QUANZHOU SANAN SEMICON TECH CO LTD

AI summary

Provided are a light emitting diode (LED) and a light emitting device. The LED includes a first semiconductor layer, an active layer and a second semiconductor layer, which are sequentially stacked in that order from bottom to top. The active layer includes AlmGa1-mN barrier layers and AlnGa1-nN well layer, which are alternately stacked periodically, and one AlmGa1-mN barrier layer and one AlnGa1-nN well layer is taken as one period to thereby form multiple periods. In at least one period of the multiple periods, a ratio of a thickness of the AlnGa1-nN well layer to a thickness of the AlmGa1-mN barrier layer is in a range of 1:3 to 1:8. By adjusting a thickness ratio of the AlnGa1-nN well layer to the AlmGa1-mN barrier layer, a combination efficiency of electrons and holes in a quantum well can be effectively improved, thus improving a luminous efficiency of the LED.