Patterned LED Epitaxy Structure for Light Extraction and Defect Reduction

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Solution Overview

Problem

Current light-emitting devices face challenges in enhancing light extraction efficiency and reducing lattice defects due to lattice mismatch between substrates and semiconductor layers, which affects the quality of epitaxial crystals and overall performance.

Innovation Solution

A light-emitting device structure comprising a substrate, a first semiconductor layer, a patterned layer, and a second semiconductor layer with a core layer of group III or transition metal material, where the second semiconductor layer is grown along the patterned layer to reduce lattice mismatch and improve bonding strength, and a reflective structure is used to enhance light extraction efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional substrate-semiconductor layer structure is used, then the device structure is simple, but light extraction efficiency is low and lattice defects increase due to lattice mismatch

Engineering Contradiction:

Improvestructure simplicityVSAvoidlight extraction efficiency

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The substrate is divided into a patterned reflective layer with periodic structures rather than a uniform surface. This segmentation creates multiple light extraction interfaces and pathways, significantly improving light extraction efficiency by reducing total internal reflection at the substrate-semiconductor interface.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A patterned reflective layer is introduced as an intermediary structure between the substrate and the semiconductor layer. This intermediate layer serves dual functions: it reflects light back into the semiconductor for extraction and provides a lattice-matched interface that reduces defect formation, thereby resolving the contradiction between structural simplicity and light extraction performance.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a patterned reflective layer is added to improve light extraction, then light extraction efficiency increases, but device complexity increases

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patterned reflective layer performs multiple functions simultaneously: it acts as a light reflector, a lattice-matched interface layer, and a structural template for the semiconductor growth. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving improved light extraction.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The reflective layer is constructed as a composite structure combining reflective material with a patterned geometry. This composite approach enables the layer to provide both optical functionality (light reflection) and structural functionality (lattice matching), achieving enhanced light extraction without proportionally increasing device complexity.

Inventive Principle:

Principle #40Composite materials

3Productivity

If semiconductor layers are grown directly on substrate, then manufacturing process is simple, but lattice defects increase due to lattice mismatch

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidlattice defect density

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patterned reflective layer is prepared in advance before semiconductor layer growth. This preliminary structure provides a pre-configured lattice-matched interface that prevents defect formation during subsequent semiconductor deposition, thereby improving manufacturing precision without significantly complicating the overall process flow.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The reflective layer is applied selectively in a patterned manner rather than as a uniform coating. This local quality approach creates regions of optimized lattice matching at the interface, reducing defect density in critical areas while maintaining manufacturing efficiency through selective deposition processes.

Inventive Principle:

Principle #3Local quality

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 proposed structure improves light extraction efficiency and reduces lattice defects, leading to enhanced performance and resource recycling by using a core layer that bonds well with the semiconductor layers and a reflective structure that increases light emission directionality.

Implementation Method 1

reduce lattice defects due to lattice mismatch between substrates and semiconductor layers

Methodology Applied

Scientific EffectLattice matching:

Implementation Method 2

core layer comprising a group III element or transition metal material formed along the first patterned layer

Methodology Applied

Scientific EffectBonding: Chemical Bonding

Implementation Method 3

reflective structure is used to enhance light extraction efficiency

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS11894487B2Light emitting device

Publication Date: 2024.02.06 ENNOSTAR CORP

AI summary

A light-emitting device comprises a substrate; a first semiconductor layer formed on the substrate; a first patterned layer formed on the first semiconductor layer; and a second semiconductor layer formed on the first semiconductor layer, wherein the second semiconductor layer comprises a core layer comprising a group III or transition metal material formed along the first patterned layer.