Transparent Conducting Oxynitride Contact Layer for Nitride LEDs

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Solution Overview

Problem

Conventional transparent conducting oxides (TCO) used in nitride-based LEDs face challenges such as high energy barriers for carrier flow, low light transmittance, especially for short wavelength lights, and difficulty in heat dissipation, limiting the efficiency and performance of LEDs.

Innovation Solution

The use of transparent conducting oxynitride (TCON) layers, comprising elements like indium, tin, zinc, and oxygen combined with nitrogen, are applied as contact layers on nitride cladding layers, with a heat process to improve ohmic contact characteristics and enhance light transmittance and reflectance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional transparent conducting oxide (TCO) or transparent conducting nitride (TCN) is used as a contact layer, then the light transmittance is improved, but a high energy barrier is formed at the interfacial surface against carrier flow, making hole injection very difficult

Engineering Contradiction:
Improvelight transmittanceVSAvoidcarrier flow efficiency
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the contact layer by incorporating nitrogen into the transparent conducting oxide to form transparent conducting oxynitride (TCON). This compositional parameter change simultaneously improves carrier flow efficiency by reducing the energy barrier at the interface while maintaining good light transmittance properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material structure by combining transparent conducting oxide with nitrogen-containing compounds to form transparent conducting oxynitride. This composite approach allows the material to exhibit both good optical transmission and improved electrical contact characteristics that neither component achieves alone.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If conventional TCO or TCN is used as an n-type nitride-based schottky or ohmic contact electrode structure, then the material is easier to manufacture, but the controlling and injecting of holes relative to the carrier flow may be difficult

Engineering Contradiction:
Improvecontact layer fabricationVSAvoidhole injection efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent modifies the chemical composition parameters of the contact layer by incorporating nitrogen into the transparent conducting oxide to form transparent conducting oxynitride (TCON). This compositional parameter change simultaneously improves carrier flow efficiency by reducing the energy barrier at the interface while maintaining good light transmittance properties.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional TCO or TCN is used as a contact layer, then the electrical conductivity is improved, but the light transmittance against light having a wavelength band equal to or lower than blue light is low

Engineering Contradiction:
Improveelectrical conductivityVSAvoidshort wavelength light transmittance
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent changes the chemical composition parameters of the contact layer by incorporating nitrogen into the transparent conducting oxide to form transparent conducting oxynitride (TCON). This compositional parameter change simultaneously improves carrier flow efficiency by reducing the energy barrier at the interface while maintaining good light transmittance properties.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If conventional TCO or TCN with a great light reflective index approximating to 2 is used as a contact layer, then the material is easier to manufacture, but emitting the light to an atmosphere through the TCO or TCN is very difficult

Engineering Contradiction:
Improvecontact layer fabricationVSAvoidlight emission efficiency
Core Design Contradiction:
Ease of manufactureVSIllumination intensity

Solution Approach 1:

The patent changes the optical parameters of the contact layer by incorporating nitrogen into the transparent conducting oxide to form transparent conducting oxynitride (TCON). This parameter change reduces the light reflective index from approximately 2 to a lower value, thereby improving light emission efficiency to the atmosphere while maintaining ease of manufacture.

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 ohmic contact characteristics, leading to higher efficiency and performance in nitride-based LEDs by reducing schottky barriers and enhancing light output, making them suitable for next-generation light sources.

Implementation Method 1

improves ohmic contact characteristics, leading to higher efficiency and performance in nitride-based LEDs by reducing schottky barriers

Methodology Applied
Scientific EffectSchottky barrier reduction:

Implementation Method 2

with a heat process to improve ohmic contact characteristics and enhance light transmittance and reflectance

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Implementation Method 3

enhancing light output, making them suitable for next-generation light sources

Methodology Applied
Scientific EffectLight transmittance enhancement:

Implementation Method 4

since conventional TCO or TCN has a great light reflective index approximating to 2, emitting the light to an atmosphere through the TCO or TCN is very difficult

Methodology Applied
Scientific EffectReflective index modification:

Data Source

PatentEP2005488B1Optical device and method of fabricating the same
Publication Date: 2013.07.31 SAMSUNG DISPLAY CO LTD
  • EP2005488B1 patent drawingFigure 1~6
  • EP2005488B1 patent drawingFigure 7~13
  • EP2005488B1 patent drawingFigure 14~21

AI summary

Disclosed is an optical device including an optical member and a contact layer stacked on at least one of top and bottom surfaces of the optical member. The contact layer has at least one transparent conducting oxynitride (TCON) layer. The TCON consists of at least one of indium (In), tin (Sn), zinc (Zn), cadmium (Cd), gallium (Ga), aluminum (Al), magnesium (Mg), titanium (Ti), molybdenum (Mo), nickel (Ni), copper (Cu), silver (Ag), gold (Au), platinum (Pt), rhodium (Rh), iridium (Ir), ruthenium (Ru), and palladium (Pd).