Large Single-Crystal Diamond Substrate via Segmented Growth

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Solution Overview

Problem

Current methods for producing large single-crystal diamond substrates face challenges in achieving uniform off-angle, crystal direction, strain distribution, and defect distribution, leading to non-uniform growth layers and low yield of semiconductor devices.

Innovation Solution

The method involves ion implantation to form a non-diamond layer on a single-crystal diamond parent substrate, followed by etching to separate child substrates with identical properties, which are then bonded using vapor-phase synthesis to create a large single-crystal diamond with uniform characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If multiple single-crystal diamond substrates are bonded using vapor-phase synthesis to increase substrate area, then the substrate area is improved, but non-uniform growth layers and defects occur due to variations in off-angle and crystal direction among substrates

Engineering Contradiction:

Improvesubstrate areaVSAvoiduniformity of growth layer

Core Design Contradiction:

Area of moving objectVSManufacturing precision

Solution Approach 1:

The invention divides a single large single-crystal diamond substrate into multiple smaller substrates by forming a non-diamond layer through ion implantation and etching. This segmentation allows the substrates to be processed and bonded while maintaining uniform crystal orientation and properties, resolving the uniformity issue when bonding multiple substrates to create large-area substrates.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention performs preliminary actions by forming a non-diamond layer through ion implantation and etching the substrate before bonding. This preliminary processing ensures that all substrates have identical crystal orientation, off-angle, and defect distribution, which prevents non-uniform growth layers when the substrates are subsequently bonded using vapor-phase synthesis.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If substrates with different off-angles and off-directions are used to increase production flexibility, then adaptability is improved, but growth layer properties become non-uniform requiring individual synthesis condition adjustments

Engineering Contradiction:

Improvesubstrate varietyVSAvoidsynthesis condition control

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention segments a uniformly oriented single-crystal substrate into multiple smaller substrates, ensuring all segments inherit the same crystal orientation and off-angle. This eliminates the need to individually adjust synthesis conditions for each substrate, reducing process complexity while maintaining substrate variety through geometric configuration rather than crystal orientation diversity.

Inventive Principle:

Principle #1Segmentation

3Ease of manufacture

If ion implantation and etching are used to separate substrates from parent substrate, then manufacturing ease is improved, but defects may be introduced into the separated substrates

Engineering Contradiction:

Improvesubstrate separationVSAvoidsubstrate quality

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention uses a non-diamond layer formed by ion implantation as an intermediary between the parent substrate and the separated substrates. This non-diamond layer acts as a sacrificial bonding interface that facilitates easy separation through etching. The key innovation is that the separated substrates maintain their crystal integrity and uniform properties because the non-diamond layer forms at a controlled depth without damaging the underlying single-crystal structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 allows for the easy production of large single-crystal diamond substrates with uniform properties, reducing processing complexity and enabling the preparation of devices with consistent quality.

Implementation Method 1

implanting ions into a parent substrate of single-crystal diamond to form a non-diamond layer near a surface of the parent substrate

Methodology Applied

Scientific EffectIon implantation: Ion Implantation

Implementation Method 2

etching the non-diamond layer to separate therefrom a single-crystal diamond layer above the non-diamond layer

Methodology Applied

Scientific EffectEtching:

Implementation Method 3

growing a single-crystal diamond by a vapor-phase synthesis method on the faces of the plurality of single-crystal diamond layers placed on the support in Step (3), thereby bonding the plurality of single-crystal diamond layers

Methodology Applied

Scientific EffectVapor-phase synthesis: Chemical Vapour Deposition

Data Source

PatentUS8940266B2Large diamond crystal substrates and methods for producing the same

Publication Date: 2015.01.27 NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE & TECHNOLOGY

AI summary

The present invention provides a method for producing a large substrate of single-crystal diamond, including the steps of preparing a plurality of single-crystal diamond layers separated form an identical parent substrate, placing the single-crystal diamond layers in a mosaic pattern on a flat support, and growing a single-crystal diamond by a vapor-phase synthesis method on faces of the single-crystal diamond layers where they have been separated from the parent substrate.According to the method of the invention, a mosaic single-crystal diamond having a large area and good quality can be produced relatively easily.