Ga2O3 Crystal Lamination Structure for Low-Defect Epitaxy

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Solution Overview

Problem

The increase in defect density of epitaxial growth layers in gallium oxide semiconductor elements leads to reduced device characteristics, such as decreased reverse withstand voltage and increased leakage current.

Innovation Solution

A crystal lamination structure is developed with a Ga2O3 single-crystal substrate and epitaxial growth layer, where both the substrate and growth layer have a (011) plane orientation, reducing defect density and enhancing device characteristics through optimized epitaxial growth methods like halide vapor phase epitaxy (HVPE).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If epitaxial growth layer is formed on gallium oxide substrate, then device functionality is achieved, but defect density increases and device characteristics deteriorate

Engineering Contradiction:

Improvedevice characteristicsVSAvoiddefect density

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by carefully controlling epitaxial growth conditions including temperature gradients, oxygen partial pressure, and growth rate to minimize defect formation in the Ga2O3 epitaxial layer while maintaining device functionality

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements local quality by creating specific structural zones within the epitaxial layer, including a first epitaxial layer with controlled doping and a second epitaxial layer with different characteristics, to optimize both device performance and defect reduction in different regions

Inventive Principle:

Principle #3Local quality

2Strength

If gallium oxide is used for high withstand voltage, then reverse withstand voltage increases, but defect density in epitaxial growth layer reduces device characteristics

Engineering Contradiction:

Improvereverse withstand voltageVSAvoiddevice characteristics

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent uses composite material structure by combining Ga2O3 substrate with carefully engineered epitaxial layers that have different compositions and doping levels, achieving both high breakdown voltage and low defect density through the synergistic combination of multiple material zones

Inventive Principle:

Principle #40Composite materials

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 configuration reduces defect density, decreases leakage current, and increases reverse withstand voltage, thereby improving device characteristics and making the semiconductor devices more efficient.

Implementation Method 1

a Ga2O3 single-crystal layer as an epitaxial growth layer provided on the first main surface of the Ga2O3 single-crystal substrate

Methodology Applied

Scientific EffectEpitaxial growth: Epitaxy

Data Source

PatentUS20240352619A1Crystal lamination structure, semiconductor device, and method of manufacturing crystal lamination structure

Publication Date: 2024.10.24 MITSUBISHI ELECTRIC CORP

AI summary

An object is to provide a technique capable of increasing device characteristics. A crystal lamination structure includes a Ga2O3 single-crystal substrate having a first main surface. The crystal lamination structure includes a Ga2O3 single-crystal layer as an epitaxial growth layer provided on the first main surface of the Ga2O3 single-crystal substrate and having a second main surface on a side opposite to the Ga2O3 single-crystal substrate. A plane direction of the first main surface of the Ga2O3 single-crystal substrate is plane. A plane direction of the second main surface of the Ga2O3 single-crystal layer is plane.