Beta-Ga2O3 Substrate Orientation for Epitaxial Quality

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Solution Overview

Problem

The challenge is to form a steep interface between the element substrate and the epitaxial layer, as well as achieve highly accurate thickness in epitaxial layers, while improving the crystalline quality of Ga-containing oxide layers on β-Ga2O3 single crystal substrates.

Innovation Solution

The use of a β-Ga2O3-based single crystal epitaxial growth substrate with a (010) plane as the main surface, which allows for the formation of a crystal laminate structure with a steep interface and highly accurate thickness through methods like MBE, enhancing the crystalline quality of the Ga-containing oxide layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a β-Ga2O3 single crystal substrate with a (100) plane is used as the main surface, then the substrate provides a flat surface easily due to high cleavability, but the crystalline quality of the Ga-containing oxide layer formed thereon deteriorates

Engineering Contradiction:
Improveease of obtaining flat surfaceVSAvoidcrystalline quality of Ga-containing oxide layer
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention changes the crystallographic orientation parameter of the substrate from (100) plane to (010) plane. This parameter change fundamentally alters the surface properties and atomic arrangement, enabling both easy fabrication of flat surfaces and high crystalline quality of the epitaxial Ga-containing oxide layer simultaneously.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If physical vapor-phase growth method (MBE) or chemical vapor-phase growth method (CVD) is used to deposit Ga-containing oxide, then the layer can be formed on the substrate, but the interface between substrate and epitaxial layer becomes gradual rather than steep

Engineering Contradiction:
Improveease of depositing Ga-containing oxide layerVSAvoidinterface steepness between substrate and epitaxial layer
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention changes the substrate surface orientation parameter from (100) to (010), which fundamentally alters the epitaxial growth characteristics. This parameter change enables the formation of steep interfaces with high precision while maintaining the effectiveness of MBE and CVD deposition methods.

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 the crystalline quality of Ga-containing oxide layers, enabling the formation of epitaxial layers with precise thickness and homogeneous element distribution, leading to improved performance in semiconductor elements such as Schottky-barrier diodes and transistors.

Implementation Method 1

an epitaxial layer formed by epitaxial growth is provided on the main surface

Methodology Applied
Scientific EffectEpitaxial growth: Epitaxy

Implementation Method 2

a physical vapor-phase growth method such as MBE (Molecular Beam Epitaxy)

Methodology Applied
Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 3

a chemical vapor-phase growth method such as CVD (Chemical Vapor Deposition)

Methodology Applied
Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentEP2754738B1Schottky-barrier diode
Publication Date: 2021.07.07 TAMURA KK
  • EP2754738B1 patent drawingFigure 1A~1B
  • EP2754738B1 patent drawingFigure 2
  • EP2754738B1 patent drawingFigure 3

AI summary

Provided is a substrate for epitaxial growth, which enables the improvement in quality of a Ga-containing oxide layer that is formed on a β-Ga2O3 single-crystal substrate. A substrate (1) for epitaxial growth comprises β-Ga2O3 single crystals, wherein face (010) of the single crystals or a face that is inclined at an angle equal to or smaller than 37.5° with respect to the face (010) is the major face. A crystal laminate structure (2) comprises: the substrate (1) for epitaxial growth; and epitaxial crystals (20) which are formed on the major face (10) of the substrate (1) for epitaxial growth and each of which comprises a Ga-containing oxide.