Single Crystal Diamond Plate Production via CVD Severing
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Solution Overview
Problem
The limitations in size and quality of natural and HPHT synthetic diamond substrates for CVD diamond growth, leading to restricted lateral dimensions and poor electronic properties due to defects and twinning, hinder the production of large, high-quality single crystal diamond plates.
Innovation Solution
A method involving homoepitaxial CVD diamond growth on a substrate with a surface substantially free of defects, followed by severing the grown diamond transverse to the substrate, allowing for the production of thick, high-purity single crystal diamond plates with linear dimensions exceeding 10 mm, and subsequent use of these plates as substrates to reduce dislocation density and enhance crystal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If natural or HPHT diamond substrates are used for CVD diamond growth, then substrate availability is improved, but lateral dimensions are limited and dislocation density increases
Solution Approach 1:
The invention segments the growth process into two distinct stages: first growing a thick layer on a small substrate, then separating this layer to create a large-area plate. This segmentation allows the substrate to serve its purpose without limiting the final product size, resolving the contradiction between substrate availability and lateral dimensions.
Solution Approach 2:
The invention transitions from two-dimensional lateral growth limited by substrate size to three-dimensional vertical growth where thickness is increased first, then the layer is separated and reconfigured into a large-area plate. This dimensional transition bypasses the substrate size constraint.
2Quantity of substance
If natural or HPHT diamond substrates are used for CVD diamond growth, then substrate availability is improved, but electronic properties deteriorate due to defects and dislocations
Solution Approach 1:
The invention extracts the CVD diamond layer from the substrate after growth, separating the high-quality grown layer from the defective substrate. This extraction removes the source of dislocations and defects, allowing the final product to have superior electronic properties while still utilizing available substrates for the growth process.
Solution Approach 2:
The invention creates a distinction between the substrate region (which can have defects) and the grown layer region (which achieves high quality). By controlling growth conditions and selectively using only the high-quality portion, the final product attains excellent electronic properties despite the substrate's limitations.
3Area of stationary object
If lateral growth is increased to achieve larger areas, then plate size is improved, but polycrystalline growth competes and degrades crystal quality
Solution Approach 1:
The invention performs preliminary vertical growth to accumulate sufficient thickness before attempting lateral expansion. This preliminary action creates a robust single crystal foundation that resists polycrystalline competition, enabling subsequent lateral growth to maintain high crystal quality while achieving larger areas.
Solution Approach 2:
The invention maintains continuous single crystal growth conditions throughout the process, avoiding interruptions that would trigger polycrystalline nucleation. By sustaining homogeneous growth conditions and using controlled separation rather than abrupt stopping, the crystal structure remains stable and high-quality throughout the expansion to larger areas.
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
Enables the fabrication of large area single crystal diamond plates with reduced dislocation density, suitable for applications requiring high crystal quality and minimal defects, such as electronic devices and optical components, by minimizing the propagation of dislocations and optimizing growth sectors.
Implementation Method 1
growing diamond homoepitaxially on the surface by chemical vapour deposition (CVD)
Data Source
AI summary
A method of producing a large area plate of single crystal diamond from CVD diamond grown on a substrate substantially free of surface defects by chemical vapor deposition (CVD). The homoepitaxial CVD grown diamond and the substrate are severed transverse to the surface of the substrate on which diamond growth took place to produce the large area plate of single crystal CVD diamond.