CVD Single Crystal Diamond with Uniform NV Centre Distribution
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Solution Overview
Problem
Existing methods struggle to produce thick layers of high-quality single crystal CVD diamond material with uniformity and high yield, particularly in the presence of nitrogen vacancies (NV centres) for quantum applications or fancy-colored gems, due to complex synthesis parameter interactions and non-uniformity in crystal morphology, growth rate, and impurity distribution.
Innovation Solution
A method involving controlled CVD growth of single crystal diamond using specific gas ratios and annealing processes to achieve a concentration of NV centres, with optional irradiation and further annealing to form NV centres, ensuring uniformity and high yield of diamonds with desired properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nitrogen is added to the CVD process gas to increase growth rate, then the growth rate of diamond material is improved, but the uniformity of crystal morphology and impurity distribution deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the nitrogen concentration in the CVD process gas (0.1-10 ppm range) and adjusting multiple synthesis parameters (temperature, pressure, gas flow rates) to achieve optimal growth conditions that maintain both high growth rate and uniform crystal morphology
Solution Approach 2:
The patent implements feedback control through real-time monitoring of synthesis parameters and growth conditions, using diagnostic tools to assess crystal quality during growth and adjusting parameters accordingly to maintain uniformity while achieving high growth rates
2Quantity of substance
If the synthesis process is extended to grow thick layers of high quality single crystal CVD diamond, then the quantity of diamond material is improved, but the stability of synthesis conditions deteriorates
Solution Approach 1:
The patent applies preliminary action by preparing substrates with specific surface treatments and orientations before growth, and pre-establishing stable synthesis regimes with optimized parameter combinations that can be maintained over extended growth periods to produce thick layers consistently
Solution Approach 2:
The patent maintains stability over extended periods by carefully controlling and adjusting synthesis parameters (temperature, pressure, gas composition) within optimal ranges, making parameter changes to compensate for drift and maintain stable growth conditions throughout long synthesis cycles
3Quantity of substance
If nitrogen doping is performed to achieve significant nitrogen levels for advantageous properties, then the concentration of nitrogen atoms is improved, but the control of NV centre formation deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling nitrogen concentration in the process gas and adjusting synthesis conditions (temperature, pressure, gas flow) to achieve desired nitrogen doping levels while maintaining uniform NV centre distribution through optimized growth kinetics
Solution Approach 2:
The patent uses feedback control to monitor nitrogen incorporation and NV centre formation during synthesis, adjusting process parameters in real-time to achieve target nitrogen concentrations while maintaining uniform distribution of NV centres throughout the crystal
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 enables the production of bulk CVD single crystal diamond with predictable properties, high growth rate, low strain, and high yield, suitable for quantum applications and fancy-colored gems, with consistent color and clarity.
Implementation Method 1
synthesis of single crystal CVD diamond material
Implementation Method 2
first annealing at least some of the resultant plurality of single crystal CVD diamonds
Implementation Method 3
irradiating the plurality of single crystal CVD diamonds to form vacancies in the diamond crystal lattice
Data Source
AI summary
A CVD single crystal diamond having a concentration of single substitutional nitrogen atoms, Ns0, in their neutral charge state as measured by EPR of between 0.25 and 3 ppm, and wherein the CVD single crystal diamond has a total concentration of nitrogen vacancy centres in their neutral and negative charge states (NV0 and NV−) that is between 0.1 and 0.8 times the Ns0 concentration.