Diamond (111) Laminate Substrate Off-Angle Epitaxy for Large-Area Growth
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Solution Overview
Problem
Current methods fail to produce high-quality, large-area single crystal diamond (111) substrates with aligned NV axes, suitable for electronic and magnetic devices, due to issues like nitrogen impurities, non-uniformity, and limited size, which hinders applications such as MRI devices.
Innovation Solution
A laminate substrate structure comprising an underlying substrate with a specific off-angle orientation, an intermediate metal film layer, and a single crystal diamond (111) layer with controlled off-angles, grown via heteroepitaxy, ensuring high crystallinity, purity, and low stress, allowing for large-diameter freestanding substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If HPHT method is used to synthesize diamond substrates, then diamond crystals can be obtained, but nitrogen impurities are present and non-uniformity occurs depending on crystal part
Solution Approach 1:
The patent introduces an intermediate layer between the substrate and the diamond crystal growth interface. This intermediate layer acts as a mediator that enables controlled heteroepitaxial growth of diamond (111) crystals with reduced impurity incorporation and improved uniformity compared to direct HPHT synthesis
Solution Approach 2:
The patent changes the growth parameters by using chemical vapor deposition (CVD) method with specific gas compositions, temperatures, and pressures to grow diamond crystals with controlled nitrogen content and improved uniformity, rather than using conventional HPHT conditions
2Manufacturing precision
If diamond (111) surface is obtained by conventional methods, then crystal orientation is achieved, but the diameter is limited to about 8 mm at most
Solution Approach 1:
The patent transitions from limited lateral growth to enhanced vertical growth by controlling the off-angle orientation of the substrate. This dimensional approach allows the crystal to grow upward with maintained orientation, enabling much larger diameter substrates to be produced without sacrificing crystallographic precision
3Adaptability or versatility
If large diameter diamond substrates are produced, then application range in MRI and sensors is expanded, but currently high quality large area single crystal diamond (111) cannot be obtained
Solution Approach 1:
The patent optimizes multiple growth parameters including substrate off-angle (within ±8 degrees from (111) plane), temperature gradients, gas flow rates, and pressure conditions to simultaneously achieve large diameter growth and high crystal quality with proper NV axis orientation for sensor applications
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 method produces high-quality single crystal diamond (111) substrates suitable for electronic and magnetic devices, with large diameter, high crystallinity, and low stress, enabling applications like high-sensitivity sensors for magnetic fields, electric fields, and pressure.
Implementation Method 1
a single crystal diamond (111) layer on the intermediate layer, wherein the underlying substrate has a main surface which has an off angle within a range, −8.0° or more and −0.5° or less, or +0.5° or more and +8.0° or less in a crystal axis [_1_1 2] direction or a threefold symmetry direction thereof relative to a crystal plane orientation of (111)
Data Source
AI summary
A method for manufacturing a laminate substrate which includes a single crystal diamond (111) layer, includes heteroepitaxially growing an intermediate layer on an underlying substrate whose main surface has an off angle within a range, −8.0° or more and −0.5° or less, or +0.5° or more and +8.0° or less in a crystal axis [_1_1 2] direction or a threefold symmetry direction thereof relative to a crystal plane orientation of (111); forming diamond nuclei on a surface of the intermediate layer; and heteroepitaxially growing, on the intermediate layer surface on which the nuclei are formed, a single crystal diamond (111) layer which has an off angle within a range, more than −10.5° and less than −2.0°, or more than +2.0° and less than +10.5° in a crystal axis [_1_1 2] direction or a threefold symmetry direction thereof relative to a crystal plane orientation of (111).