GaAs Crystal Oxygen Control for Conductivity and Integrity

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Solution Overview

Problem

High oxygen concentration in GaAs source material melts leads to inefficient dopant incorporation, affecting the insulating properties and conductivity of GaAs crystals, and increases the likelihood of crystal cracking during processing, resulting in decreased processing yields.

Innovation Solution

A gallium arsenide crystal body and substrate with controlled etching pit density and oxygen concentration, specifically between 10 cm^-2 and 10000 cm^-2 and less than 7.0×10^15 atoms/cm^-3, respectively, are developed using a manufacturing apparatus with a reduced number of inter-heater gaps and a closure plate to minimize oxygen incorporation, ensuring efficient adjustment of insulating properties and conductivity while preventing cracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If oxygen concentration in GaAs source material melt is increased, then insulating property adjustment becomes inefficient, but crystal growth speed improves

Engineering Contradiction:
Improveinsulating property adjustment efficiencyVSAvoidcrystal growth speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes the oxygen concentration parameter in the GaAs source material melt to a specific range (5×10^14 to 5×10^15 atoms/cm³) to optimize both insulating property adjustment efficiency and crystal growth speed. By precisely controlling this parameter, the invention resolves the contradiction between efficient dopant incorporation and productive crystal growth.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If oxygen concentration in GaAs source material melt is increased, then crystal growth is enhanced, but crystal cracking likelihood increases

Engineering Contradiction:
Improvecrystal growthVSAvoidcrystal integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent optimizes the oxygen concentration parameter to a specific range that enables sufficient crystal growth while preventing excessive oxygen that would cause hardening and cracking. This precise parameter control resolves the contradiction between productive crystal growth and reliable crystal integrity.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If dopant concentration is increased to adjust insulating property, then conductivity control improves, but oxygen-dopant reaction increases

Engineering Contradiction:
Improveconductivity controlVSAvoiddopant loss
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the oxygen concentration parameter to a lower optimal range, which reduces the harmful reaction between oxygen and dopants. This allows for effective conductivity control through dopant addition while minimizing dopant loss to oxygen reactions, resolving the contradiction between reliable conductivity control and substance preservation.

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 approach allows for efficient adjustment of insulating properties and conductivity, reducing the likelihood of crystal cracking and enhancing processing yields by maintaining low etching pit density and oxygen concentration, even in large-diameter GaAs crystals.

Implementation Method 1

a carbon concentration in the GaAs crystal is adjusted by adjusting an oxygen concentration in a GaAs source material melt

Methodology Applied
Scientific EffectDopant incorporation: Dopants

Data Source

PatentEP4063541A1Gallium arsenide crystal body and gallium arsenide crystal substrate
Publication Date: 2022.09.28 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP4063541A1 patent drawingFigure 1~2
  • EP4063541A1 patent drawingFigure 3
  • EP4063541A1 patent drawingFigure 4

AI summary

A gallium arsenide crystal body, wherein an etching pit density of the gallium arsenide crystal body is more than or equal to 10 cm-2 and less than or equal to 10000 cm-2, an oxygen concentration of the gallium arsenide crystal body is less than 7.0×1015 atoms·cm-3, and an n type conductivity impurity concentration of the gallium arsenide crystal body is more than or equal to 1.0×1015 atoms·cm-3 and less than or equal to 1.0×1020 atoms·cm-3.