GaN LED Translucent Electrode Annealing Resistance

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Solution Overview

Problem

Gallium nitride compound semiconductor light-emitting devices face challenges with increased specific resistance of p-type semiconductor layers due to hydrogen annealing, which affects the driving voltage and light emission efficiency.

Innovation Solution

A method involving the formation of a translucent conductive oxide film on a p-type semiconductor layer, followed by a hydrogen annealing process in a gas atmosphere, which reduces the specific resistance of the oxide film and prevents increased resistance in the p-type layer, thereby lowering the driving voltage. This process includes forming, etching, and annealing the oxide film in specific temperature and gas concentration conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a translucent conductive oxide film (such as ITO) is used as a positive electrode to improve light transmittance, then light emission efficiency is improved, but the specific resistance of the electrode increases

Engineering Contradiction:
Improvelight transmittanceVSAvoidspecific resistance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent applies parameter changes by performing annealing treatment on the ITO film at specific temperatures (400-900°C) in a nitrogen or hydrogen atmosphere. This thermal treatment modifies the physical and electrical parameters of the ITO film, reducing its specific resistance from typically high values to below 10^-3 Ω·cm, while preserving its high light transmittance properties. The annealing process optimizes the balance between electrical conductivity and optical transparency.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If a translucent positive electrode is used to allow light emission to the outside, then light emission efficiency is improved, but the contact resistance with the p-type semiconductor layer increases

Engineering Contradiction:
Improvelight emission efficiencyVSAvoidcontact resistance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent utilizes parameter changes through annealing treatment to modify the electrical properties of the ITO film. By controlling the annealing temperature (400-900°C) and atmosphere (nitrogen or hydrogen), the specific resistance of the ITO film is reduced to below 10^-3 Ω·cm. This dramatic reduction in resistance enables the ITO film to serve as both a translucent electrode for light emission and a low-resistance contact with the p-type semiconductor layer, resolving the contradiction between transparency and conductivity.

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

The method results in a gallium nitride compound semiconductor light-emitting device with reduced specific resistance and driving voltage, enhancing light emission characteristics and efficiency.

Implementation Method 1

A method is provided in which a translucent conductive oxide film is formed on a p-type semiconductor layer of a gallium nitride compound semiconductor device. After the translucent conductive oxide film is formed on the p-type semiconductor layer, a hydrogen annealing process of annealing the film in a gas atmosphere including hydrogen (H2) is performed.

Methodology Applied
Scientific EffectAnnealing: Annealing

Implementation Method 2

In the annealing process performed in the gas atmosphere including hydrogen, hydrogen is bonded to Mg or Zn doped into a p-type semiconductor layer of a gallium nitride compound semiconductor light-emitting device, and hinders impurities, such as Mg or Zn, from serving as acceptors.

Methodology Applied
Scientific EffectHydrogen bonding:

Data Source

PatentEP1998381B1Method for manufacturing gallium nitride compound semiconductor light-emitting device and lamp using same
Publication Date: 2018.01.31 TOYODA GOSEI CO LTD
  • EP1998381B1 patent drawingFigure 1~2
  • EP1998381B1 patent drawingFigure 3~4
  • EP1998381B1 patent drawingFigure 5~6

AI summary

The present invention provides a gallium nitride compound semiconductor light-emitting device that prevents an increase in the specific resistance of a p-type semiconductor layer due to hydrogen annealing and reduces the specific resistance of a translucent conductive oxide film to lower a driving voltage Vf, a method of manufacturing the same, and a lamp including the same. The method of manufacturing the gallium nitride compound semiconductor light-emitting device includes: forming a positive electrode 15 composed of a translucent conductive oxide film on a p-type GaN layer 14 of a gallium nitride compound semiconductor device; and a hydrogen annealing process of annealing the positive electrode 15 in a gas atmosphere including hydrogen (H2).