Nanorod LED Structure for Uniform Etching and Current Confinement

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Solution Overview

Problem

Existing micro-LED technologies face challenges in achieving uniform nano-scale dimensions and efficient current distribution, leading to surface defects and reduced luminous efficiency due to high surface-to-volume ratios and non-uniform etching processes.

Innovation Solution

The implementation of a nanorod light emitting device with a conductor layer and current blocking layers, along with a passivation layer, to enhance current concentration and reduce surface defects, combined with controlled etching using inclined hard masks to maintain uniform diameter and smooth surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional micro-LED fabrication processes are used, then basic light emitting function is achieved, but uniform nano-scale dimensions and efficient current distribution cannot be achieved, leading to surface defects and reduced luminous efficiency

Engineering Contradiction:
Improveuniformity of nano-scale dimensionsVSAvoidluminous efficiency
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The invention segments the etching process into multiple stages with different etching conditions. A first etching process creates an initial structure, followed by a second etching process with modified parameters to achieve the final uniform nanorod shape. This multi-stage segmentation allows precise control over dimension uniformity while maintaining structural integrity for reliable light emission.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes etching parameters between processing stages, including gas flow rates, power levels, and pressure conditions. By adjusting these parameters sequentially, the process achieves both the required nano-scale dimensional uniformity and the structural quality necessary for high luminous efficiency, resolving the contradiction between precision and reliability.

Inventive Principle:
Principle #35Parameter changes

2Length of moving object

If high surface-to-volume ratio nanorod structure is used, then nano-scale size is achieved, but surface defects increase due to non-uniform etching processes

Engineering Contradiction:
Improvenanorod sizeVSAvoidsurface uniformity
Core Design Contradiction:
Length of moving objectVSManufacturing precision

Solution Approach 1:

The invention performs preliminary etching to create a controlled initial nanorod structure before applying final etching steps. This preliminary action establishes the basic nanoscale dimensions while leaving room for subsequent refinement, ensuring surface uniformity is achieved without compromising the required small nanorod size.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention employs dynamic adjustment of etching parameters during the process, transitioning from aggressive etching conditions that rapidly reduce material to gentle finishing conditions that smooth surfaces. This dynamic parameter control maintains nanoscale dimensions while eliminating surface defects that would otherwise arise from the high surface-to-volume ratio.

Inventive Principle:
Principle #15Dynamics

3Productivity

If conventional etching processes are used, then material removal is achieved, but non-uniform etching leads to surface defects and reduced performance

Engineering Contradiction:
Improvematerial removal efficiencyVSAvoidetching uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention implements periodic alternation between different etching modes - a powerful etching mode for rapid material removal followed by a gentle etching mode for surface smoothing. This periodic switching maintains high overall productivity while ensuring etching uniformity, preventing surface defects that would result from using a single continuous etching mode.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The invention maintains continuous etching action throughout the process, avoiding complete stops that would disrupt uniformity. By continuously adjusting parameters rather than interrupting the process, the system achieves both high material removal rates and uniform etching quality, resolving the productivity-precision contradiction.

Inventive Principle:
Principle #20Continuity of useful action

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 results in a nanorod light emitting device with improved luminous efficiency and uniform dimensions, minimizing surface defects and enhancing current distribution, thereby improving overall performance.

Implementation Method 1

a current blocking layer disposed to surround a sidewall of the conductor layer

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

A plurality of passivation layers may be disposed to surround side surfaces of the first semiconductor layer, the current blocking layer, the light emitting layer, and the second semiconductor layer

Methodology Applied
Scientific EffectPassivation:

Implementation Method 3

a light emitting layer disposed between the first semiconductor layer and the second semiconductor layer

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3993068B1Nanorod light emitting device, method of manufacturing the same, and display apparatus including the same
Publication Date: 2026.02.18 SAMSUNG DISPLAY CO LTD
  • EP3993068B1 patent drawingFigure 1A
  • EP3993068B1 patent drawingFigure 1B
  • EP3993068B1 patent drawingFigure 1C

AI summary

A nanorod light emitting device, a method of manufacturing the same, and a display apparatus including the nanorod light emitting device are provided. The nanorod light emitting device includes a first semiconductor layer doped with a first conductivity type, a light emitting layer disposed on the first semiconductor layer, and a second semiconductor layer disposed on the light emitting layer and doped with a second conductivity type that is electrically opposite to the first conductivity type, wherein a distance between a lower surface of the first semiconductor layer and an upper surface of the second semiconductor layer is in a range of about 2 µm to about 10 µm, wherein a difference between a diameter of the upper surface of the second semiconductor layer and the lower surface of the first semiconductor layer is 10% or less of a diameter of the upper surface of the second semiconductor layer.