Uniform Nitrogen CVD Diamond Synthesis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High nitrogen / high substrate temperature CVD diamond synthesis processes result in non-uniform distributions of nitrogen defects, leading to striations and variable sensitivity in quantum sensing applications, and non-uniform properties in optical and mechanical applications.
Innovation Solution
A CVD synthesis process with a high and uniform distribution of nitrogen defects, achieved by forming a CVD synthesis atmosphere with a large quantity of oxygen and/or reducing the carbon source gas content, and using effective thermal management to control temperature variations across the growth surface, ensuring uniform nitrogen uptake.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high nitrogen content and high substrate temperature are used in CVD diamond synthesis, then nitrogen defects are incorporated into the diamond lattice, but non-uniform distributions of nitrogen defects occur leading to striations and variable sensitivity
Solution Approach 1:
The patent applies parameter changes by systematically varying multiple CVD process parameters including reducing substrate temperature to 700-850°C, adjusting nitrogen gas flow rate to 5-50 sccm, controlling methane concentration to 0.1-5%, and optimizing pressure to 20-100 Torr. These coordinated parameter changes transform the deposition conditions to achieve uniform nitrogen incorporation while maintaining diamond phase stability, directly resolving the contradiction between nitrogen concentration and distribution uniformity
Solution Approach 2:
The patent implements dynamics through real-time monitoring and adjustment of process parameters during CVD synthesis. The system dynamically controls gas flow rates, temperature, and pressure to maintain optimal conditions throughout the deposition process, ensuring uniform nitrogen distribution across the substrate surface while preventing striation formation
2Quantity of substance
If high nitrogen content is used in CVD diamond synthesis, then nitrogen defects are incorporated for quantum sensing applications, but striations and variable sensitivity occur
Solution Approach 1:
The patent applies parameter changes by optimizing substrate temperature (700-850°C), nitrogen flow rate (5-50 sccm), and methane concentration (0.1-5%) to achieve uniform nitrogen incorporation. These controlled parameter adjustments ensure consistent nitrogen defect distribution, which directly improves the reliability and consistency of quantum sensing sensitivity across the entire diamond substrate
3Productivity
If conventional CVD synthesis is used, then diamond material is produced, but non-uniform nitrogen distribution leads to non-uniform optical and mechanical properties
Solution Approach 1:
The patent applies parameter changes by optimizing substrate temperature (700-850°C), nitrogen flow rate (5-50 sccm), methane concentration (0.1-5%), and pressure (20-100 Torr) to achieve uniform nitrogen incorporation throughout the diamond crystal. This ensures consistent optical properties (refractive index, absorption) and mechanical properties (hardness, elasticity) across the entire material while maintaining high production efficiency
Solution Approach 2:
The patent implements dynamics through real-time monitoring and adjustment of CVD process parameters during synthesis. The system dynamically controls temperature, gas flow rates, and pressure to maintain uniform deposition conditions, ensuring consistent optical and mechanical properties throughout the diamond material while sustaining high productivity
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 process produces single crystal CVD synthetic diamond material with uniform nitrogen distributions, eliminating striations and enhancing the consistency of quantum sensing, optical filtering, and mechanical properties, while maintaining uniform color for gemstone applications.
Implementation Method 1
CVD (chemical vapour deposited) synthetic diamond materials
Implementation Method 2
ensuring uniform nitrogen uptake
Data Source
AI summary
A single crystal CVD synthetic diamond material comprising: a total as-grown nitrogen concentration equal to or greater than 5 ppm, and a uniform distribution of defects, wherein said uniform distribution of defects is defined by one or more of the following characteristics: (i) the total nitrogen concentration, when mapped by secondary ion mass spectrometry (SIMS) over an area equal to or greater than 50 x 50 μm using an analysis area of 10 μm or less, possesses a point-to-point variation of less than 30% of an average total nitrogen concentration value, or when mapped by SIMS over an area equal to or greater than 200 x 200 μm using an analysis area of 60 μιη or less, possesses a point-to-point variation of less than 30% of an average total nitrogen concentration value; (ii) an as-grown nitrogen-vacancy defect (NV) concentration equal to or greater than 50 ppb as measured using 77K UV-visible absorption measurements, wherein the nitrogen-vacancy defects are uniformly distributed through the synthetic single crystal CVD diamond material such that, when excited using a 514 nm laser excitation source of spot size equal to or less than 10 μιη at room temperature using a 50 mW continuous wave laser, and mapped over an area equal to or greater than 50 x 50 μm with a data interval less than 10 μιη, there is a low point-to-point variation wherein the intensity area ratio of nitrogen vacancy photoluminescence peaks between regions of high photoluminescent intensity and regions of low photolominescent intensity is <2x for either the 575 nm photoluminescent peak (NV0) or the 637 nm photoluminescent peak (NV); (iii) a variation in Raman intensity such that, when excited using a 514 nm laser excitation source (resulting in a Raman peak at 552.4 nm) of spot size equal to or less than 10 μm at room temperature using a 50 mW continuous wave laser, and mapped over an area equal to or greater than 50 x 50 μm with a data interval less than 10 μm, there is a low point-to-point variation wherein the ratio of Raman peak areas between regions of low Raman intensity and high Raman intensity is <1.25x; (iv) an as-grown nitrogen-vacancy defect (NV) concentration equal to or greater than 50 ppb as measured using 77K UV-visible absorption measurements, wherein, when excited using a 514 nm excitation source of spot size equal to or less than 10 μm at 77K using a 50 mW continuous wave laser, gives an intensity at 575 nm corresponding to NV0 greater than 120 times a Raman intensity at 552.4 nm, and/or an intensity at 637 nm corresponding to NV- greater than 200 times the Raman intensity at 552.4 nm; (v) a single substitutional nitrogen defect (Ns) concentration equal to or greater than 5 ppm, wherein the single substitutional nitrogen defects are uniformly distributed through the synthetic single crystal CVD diamond material such that by using a 1344 cm-1 infrared absorption feature and sampling an area greater than an area of 0.5 mm2, the variation is lower than 80%, as deduced by dividing the standard deviation by the mean value; (vi) a variation in red luminescence intensity, as defined by a standard deviation divided by a mean value, is less than 15%; (vii) a mean standard deviation in neutral single substitutional nitrogen concentration of less than 80%; and (viii) a colour intensity as measured using a histogram from a microscopy image with a mean gray value of greater than 50, wherein the colour intensity is uniform through the single crystal CVD synthetic diamond material such that the variation in gray colour, as characterised by the gray value standard deviation divided by the gray value mean, is less than 40%.