Thick Single Crystal CVD Diamond via Segmented Growth
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Solution Overview
Problem
Current methods for synthesizing single crystal chemical vapor deposited (CVD) diamond materials are limited by the size of available substrates and the presence of defects, which restrict the growth of larger, high-quality diamond layers.
Innovation Solution
A method involving multiple CVD diamond growth processes, where single crystal diamond substrates are first grown to a moderate thickness and then mounted in a recessed carrier substrate for further growth, allowing for the production of larger, thicker, high-quality single crystal CVD diamonds by mutually shielding the substrates from the plasma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a single crystal diamond substrate is grown to increase thickness, then the thickness of the diamond layer is improved, but plasma stability and temperature control deteriorate
Solution Approach 1:
The growth process is divided into multiple stages with intermediate processing steps. After growing a first thickness (e.g., 3mm), the substrate is removed, processed (laser trimming, mounting in recessed carrier), and then grown again. This segmentation allows maintaining plasma stability while achieving greater total thickness through cumulative growth cycles.
Solution Approach 2:
Before the second growth stage, preliminary actions are performed including laser trimming to precise dimensions, mounting in recessed carrier substrates, and surface preparation. These preliminary actions ensure optimal starting conditions for the second growth stage, enabling continued plasma stability and temperature control while building upon the first growth stage.
2Area of stationary object
If the size of single crystal diamond substrates is increased, then the lateral size of the product is improved, but the availability of defect-free substrates deteriorates
Solution Approach 1:
Multiple small single crystal diamond substrates (e.g., 10mm×10mm) are mounted in close proximity within a single recessed carrier substrate. During CVD growth, these substrates grow simultaneously and can laterally coalesce to form a large-area single crystal diamond structure. This merging approach produces large lateral dimensions while maintaining the low defect concentration of the original small substrates.
Solution Approach 2:
The small single crystal substrates serve as self-contained nucleation sites that automatically guide the growth of adjacent regions. As diamond material deposits on multiple substrates, the crystal structure naturally extends laterally from each substrate, with the substrates themselves serving as the template for their own expansion and for the expansion of neighboring substrates, resulting in large-area single crystal formation without requiring a large initial substrate.
3Length of moving object
If a thick layer of single crystal CVD diamond is grown vertically, then the size of substrates and products is improved, but the concentration of dislocation defects increases
Solution Approach 1:
The vertical growth is segmented into multiple stages with intermediate processing. After the first growth stage reaches a moderate thickness, the substrate is removed, processed (including potential orientation correction and surface preparation), and then mounted for the second growth stage. This segmentation interrupts the continuous vertical growth, preventing dislocation propagation through the entire thickness and allowing fresh nucleation sites to be prepared for the next growth phase.
Solution Approach 2:
Between growth stages, preliminary actions include laser trimming to precise dimensions, mounting in recessed carrier substrates, and surface preparation. These actions reset the growth conditions and prepare fresh surfaces for the next growth stage, ensuring that dislocation defects do not accumulate continuously through the entire thickness but are instead managed in discrete segments.
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 enables the commercially viable production of large, high-quality single crystal CVD diamonds, overcoming size and defect limitations, and facilitating their use in various applications such as optical components and high-power devices.
Implementation Method 1
Single crystal CVD diamond products are limited by the available size of single crystal diamond growth substrates
Implementation Method 2
the thickness of the single crystal CVD diamond layer which can be grown thereon is limited by issues such as plasma stability
Data Source
AI summary
A method of fabricating a plurality of single crystal CVD diamonds. The method includes mounting a plurality of single crystal diamond substrates on a first carrier substrate. The plurality of single crystal diamond substrates is subjected to a first CVD diamond growth process to form a plurality of single crystal CVD diamonds on the plurality of single crystal diamond substrates. The plurality of single crystal CVD diamonds are mounted in a recessed carrier substrate and subjected to a second CVD diamond growth process.