Multicolor GaN LED Matrix Epitaxy on a Sacrificial Layer

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Solution Overview

Problem

Existing methods for manufacturing GaN-based LEDs are complex and costly, particularly for miniaturized LEDs, which face challenges such as full-color operation, reduced external quantum efficiency, and power leakage due to non-uniformity and cutting damage.

Innovation Solution

A method for forming a matrix of GaN-based LEDs of different colors by epitaxially growing first, second, and third arrays of LED elements on a sacrificial GaN layer, using a stacked structure of n-doped, p-doped GaN layers, and InxGa(1-x)N layers with varying indium compositions to control the wavelength of emitted light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional sapphire substrates are used for blue LED growth, then high manufacturing costs are incurred, but good crystal quality is achieved

Engineering Contradiction:
Improvecrystal qualityVSAvoidsubstrate cost
Core Design Contradiction:
Manufacturing precisionVSWeight of stationary object

Solution Approach 1:

The patent changes the material parameter of the substrate from conventional sapphire to silicon carbide, which has different physical and chemical properties that enable both low-cost manufacturing and high-quality crystal growth for blue LEDs

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs silicon carbide substrates that are cheaper than sapphire, making the substrate a cost-effective, disposable component that can be replaced without significant expense, thereby reducing overall manufacturing costs while maintaining product quality

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If multiple single-crystal substrates are used for different coloured LEDs, then colour specificity is maintained, but device complexity increases

Engineering Contradiction:
Improvecolour specificityVSAvoidsubstrate integration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the silicon carbide substrate universal by demonstrating its ability to grow high-quality crystals for multiple LED colours (blue, green, red) on a single substrate type, eliminating the need for different substrate materials for different colours and thereby reducing device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the function of multiple colour-specific substrates into a single multi-functional silicon carbide substrate, allowing simultaneous or sequential growth of different coloured LED structures on one substrate type, which simplifies the overall device architecture and integration process

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If epitaxial growth is performed at high temperatures, then crystal quality improves, but substrate distortion increases

Engineering Contradiction:
Improveepitaxial layer qualityVSAvoidsubstrate distortion
Core Design Contradiction:
Manufacturing precisionVSShape

Solution Approach 1:

The patent changes the thermal and mechanical parameters of the substrate system by using silicon carbide instead of sapphire, which has superior thermal stability and mechanical strength, allowing high-temperature epitaxial growth to proceed without excessive substrate distortion

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a template or model substrate structure on the silicon carbide that guides the epitaxial growth process, allowing high-quality crystal formation at elevated temperatures while the substrate itself remains dimensionally stable due to its inherent material properties

Inventive Principle:
Principle #26Copying

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 method enables integrated processing of LEDs of different colors on the same substrate, improving luminance balance and efficiency, and reducing manufacturing complexity and cost, while allowing for the production of high-resolution displays.

Implementation Method 1

A method for the production of a matrix of light-emitting diode (LED) elements of different colours comprising: providing a matrix of silicon carbide substrates... subsequent epitaxial growth of gallium nitride layers

Methodology Applied
Scientific EffectEpitaxial growth: Epitaxy

Data Source

PatentEP4327365B1Method for forming a matrix of light-emitting diode elements of different colours
Publication Date: 2025.03.05 EPINOVATECH AB
  • EP4327365B1 patent drawingFigure 1~3
  • EP4327365B1 patent drawingFigure 4~6
  • EP4327365B1 patent drawingFigure 7~9

AI summary

A method for forming a matrix of light-emitting diode (LED) elements (11, 21, 31) of different colours is provided. The method comprises epitaxially growing, on a GaN sacrificial layer (140), a first n-doped GaN layer (111), a first lnxGa(1-X)N layer (112) and a first p-doped GaN layer (113) to form a first array of first LED elements (11) for emitting light of a first colour, and forming a first etch mask (151) comprising a plurality of first trenches (161). The method further comprises: epitaxially growing a second array of second LED elements (21), for emitting light of a second colour, in the plurality of first trenches; forming a second etch mask (152) protecting the second array and comprising a plurality of second trenches (162); and epitaxially growing a third array of third LED elements (31), for emitting light of a third colour, in the plurality of second trenches.