GaAs Single Crystal Substrate Growth With Low Dislocation Density

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Solution Overview

Problem

Existing methods struggle to produce gallium arsenide single crystal substrates with sufficiently reduced dislocation density, making it difficult to achieve large-sized substrates with improved performance.

Innovation Solution

Control the temperature at the interface between the seed crystal and the raw material melt during the VB method to suppress dislocations, ensuring the gallium arsenide single crystal substrate has a reduced dislocation density and large size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional VB method is used to grow gallium arsenide single crystal, then large-sized substrates can be produced, but the dislocation density remains high

Engineering Contradiction:
Improvedislocation densityVSAvoiddifficulty to suppress dislocations
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by precisely controlling the temperature at the interface between the seed crystal and raw material melt during the VB method. By optimizing temperature parameters, the invention suppresses dislocation formation at the crystal-growth interface, achieving low dislocation density in large-sized substrates while maintaining manufacturing feasibility

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies local quality by focusing temperature control specifically at the interface region between the seed crystal and raw material melt, rather than uniform temperature control throughout the entire system. This localized temperature management targets the critical area where dislocations originate, effectively reducing dislocation density in the grown crystal

Inventive Principle:
Principle #3Local quality

2Reliability

If dislocation density is reduced to improve device performance, then electrical and optical characteristics improve, but the substrate size is limited

Engineering Contradiction:
Improveelectrical and optical characteristicsVSAvoidsubstrate size
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

By changing and optimizing the temperature parameter at the crystal-growth interface, the invention simultaneously achieves low dislocation density and large substrate size. The controlled temperature gradient allows dislocation suppression across the entire growth front, enabling large-area substrates with improved electrical and optical characteristics

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 enables the production of gallium arsenide single crystal substrates with low dislocation density, allowing for larger substrates with improved electrical and optical characteristics, enhancing semiconductor device performance.

Implementation Method 1

when the diameter of the main surface of the gallium arsenide single crystal substrate is represented by D and the number of etch pits formed on the main surface by immersing the gallium arsenide single crystal substrate in molten potassium hydroxide at 500°C for 10 minutes is counted

Methodology Applied
Scientific EffectEtching:

Implementation Method 2

a raw material contained in a crucible is melted with heat, and then a single crystal is manufactured by solidifying the material from one direction

Methodology Applied
Scientific EffectMelting and Solidification: Melting

Implementation Method 3

The heater is provided for the purpose of heating the ampule and the crucible

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP3998377B1Gallium arsenide single crystal substrate
Publication Date: 2026.03.25 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP3998377B1 patent drawingFigure 1~2
  • EP3998377B1 patent drawingFigure 3
  • EP3998377B1 patent drawingFigure 4

AI summary

The gallium arsenide single crystal substrate has a circular main surface, and when the diameter of the main surface of the gallium arsenide single crystal substrate is represented by D and the number of etch pits formed on the main surface by immersing the gallium arsenide single crystal substrate in molten potassium hydroxide at 500°C for 10 minutes is counted, the number C1 of etch pits in a first circular region having a diameter of 0.2D around the center of the main surface is 0 or more and 10 or less.