Indium Phosphide Substrate Oxygen Control via Boron Oxide Film

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Solution Overview

Problem

Existing indium phosphide (InP) single-crystal substrates have high oxygen concentrations, leading to the formation of oxide layers with insulating properties, which increases resistance and reduces the response speed of semiconductor devices.

Innovation Solution

An indium phosphide single-crystal body and substrate with an oxygen concentration of less than 1×10^16 atoms/cm^3, achieved through a manufacturing process using a crucible with a boron oxide film and a closure plate to minimize oxygen incorporation during crystal growth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional manufacturing methods are used for InP single-crystal substrates, then production is feasible with standard processes, but oxygen concentration becomes high (1×10^17 to 1×10^18 atoms/cm³) leading to oxide layer formation

Engineering Contradiction:
Improveoxygen concentration controlVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

A boron oxide film is formed on the inner surface of the crucible before crystal growth begins. This preliminary action prevents oxygen incorporation during the subsequent crystal growth process, achieving low oxygen concentration (less than 1×10^16 atoms/cm³) in the final InP single-crystal substrate without requiring complex post-processing

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A closure plate is introduced as an intermediary component between the molten InP and the crucible environment. This closure plate prevents direct contact between the molten material and oxygen-containing atmosphere, thereby preventing oxide formation during crystal growth while maintaining a relatively simple manufacturing process

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If oxygen concentration is reduced to less than 1×10^16 atoms/cm³, then oxide layer formation is suppressed and device characteristics improve, but manufacturing process becomes more complex

Engineering Contradiction:
Improvesemiconductor device characteristicsVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The boron oxide film is prepared in advance on the crucible inner surface before crystal growth. This preliminary coating creates an oxygen barrier that ensures low oxygen concentration in the grown crystal, improving device reliability (electron mobility greater than 6000 cm²/Vs) while keeping the overall process manageable through straightforward implementation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The boron oxide film creates an inert-like protective environment on the crucible surface, preventing oxygen from the surrounding atmosphere from incorporating into the molten InP during crystal growth. This achieves the desired low oxygen concentration and high device reliability without requiring extremely complex vacuum or atmosphere control systems

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

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 low oxygen concentration suppresses the formation of oxide layers and composite states, resulting in semiconductor devices with improved characteristics, including reduced resistance and enhanced response speed.

Implementation Method 1

a crucible with a boron oxide film to minimize oxygen incorporation during crystal growth

Methodology Applied
Scientific EffectOxidation resistance: Oxidation

Implementation Method 2

a closure plate to minimize oxygen incorporation during crystal growth

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Implementation Method 3

The low oxygen concentration suppresses the formation of oxide layers and composite states

Methodology Applied
Scientific EffectOxide suppression: Oxidation

Data Source

PatentEP3502323B1Indium phosphide single crystal body and indium phosphide single crystal substrate
Publication Date: 2025.02.19 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP3502323B1 patent drawingFigure 1~2
  • EP3502323B1 patent drawingFigure 3

AI summary

An indium phosphide single-crystal body has an oxygen concentration of less than 1×1016 atoms·cm-3, and includes a straight body portion having a cylindrical shape, wherein a diameter of the straight body portion is more than or equal to 100 mm and less than or equal to 150 mm or is more than 100 mm and less than or equal to 150 mm. An indium phosphide single-crystal substrate has an oxygen concentration of less than 1×1016 atoms·cm-3, wherein a diameter of the indium phosphide single-crystal substrate is more than or equal to 100 mm and less than or equal to 150 mm or is more than 100 mm and less than or equal to 150 mm.