Ga2O3 Diode With NiO pn Heterojunction for Low-Cost Fabrication

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Solution Overview

Problem

The formation of a pn homojunction in Ga 2 O 3 -based diodes is difficult, and existing pn heterojunction diodes are costly to produce.

Innovation Solution

A Ga 2 O 3 -based diode utilizing a pn heterojunction is produced using a p-type semiconductor film with a higher amorphous portion than crystalline portion, formed at lower temperatures, and incorporating NiO as the p-type semiconductor material, which is thermodynamically stable and allows for stable p-type layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pn homojunction is formed in Ga 2 O 3 -based diodes, then rectification function is achieved, but formation is difficult and cost is high

Engineering Contradiction:
Improverectification functionVSAvoidformation difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent introduces a p-type semiconductor layer as an intermediary between the n-type Ga 2 O 3 substrate and the metal electrode. This p-type layer enables the formation of a pn heterojunction with the n-type substrate, providing a stable rectification interface that is easier to manufacture than direct homojunctions while maintaining reliable rectification function.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a composite structure combining n-type Ga 2 O 3 substrate with a p-type semiconductor layer. This composite pn heterojunction structure leverages the advantages of both materials to achieve stable rectification with improved manufacturability compared to homogeneous structures.

Inventive Principle:
Principle #40Composite materials

2Reliability

If existing pn heterojunction diodes are produced, then rectification function is achieved, but production cost is high

Engineering Contradiction:
Improverectification functionVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent optimizes parameters such as the thickness and doping concentration of the p-type semiconductor layer to achieve effective rectification with reduced material costs. By carefully controlling these parameters, the patent maintains reliable rectification function while lowering production costs compared to conventional heterojunction diodes.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If p-type semiconductor layer is formed with high crystalline portion, then layer stability is improved, but formation temperature increases and manufacturing cost rises

Engineering Contradiction:
Improvelayer stabilityVSAvoidformation temperature
Core Design Contradiction:
Stability of the object's compositionVSTemperature

Solution Approach 1:

The patent changes the crystalline structure parameters of the p-type semiconductor layer, specifically utilizing an amorphous structure with controlled composition. This approach achieves sufficient layer stability for reliable operation while avoiding the high formation temperatures required for fully crystalline structures, thereby reducing manufacturing costs.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If amorphous p-type semiconductor layer is used, then formation temperature is reduced and cost is lowered, but leakage current increases

Engineering Contradiction:
Improveformation temperatureVSAvoidleakage current
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent optimizes the composition parameters of the amorphous p-type semiconductor layer, specifically controlling the ratio of Ga to O atoms and the doping concentration. By carefully adjusting these parameters, the patent achieves sufficient electrical stability to suppress leakage current while maintaining the lower formation temperature and cost advantages of amorphous structures.

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 diode can be easily produced at low cost while effectively suppressing leakage current and achieving high withstand voltage without increasing resistance.

Implementation Method 1

a pn junction diode which utilize the rectification property of a pn heterojunction formed between the n-type β-Ga 2 O 3 single crystal and the p-type NiO single crystal

Methodology Applied
Scientific EffectRectification property of pn heterojunction: Diode

Data Source

PatentEP3667737B1diode
Publication Date: 2025.10.15 TAMURA KK
  • EP3667737B1 patent drawingFigure 1
  • EP3667737B1 patent drawingFigure 2
  • EP3667737B1 patent drawingFigure 3A~3C

AI summary

Provided is a Ga2O3 diode which utilizes a pn heterojunction, and which is able to be easily produced at low cost. One embodiment of the present invention provides a diode 2 which is provided with: an n-type semiconductor layer 21 that is composed of an n-type Ga2O3 single crystal; and a p-type semiconductor layer 22 that is composed of a p-type semiconductor wherein the volume of amorphous portions is higher than the volume of crystalline portions. With respect to this diode 2, the n-type semiconductor layer 21 and the p-type semiconductor layer 22 form a pn junction.