CVD Diamond Synthesis via Nitrogen and Oxygen Gas Control
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Solution Overview
Problem
Current CVD diamond synthesis methods, such as HPHT and traditional CVD, face challenges in achieving uniform nitrogen distribution, high nitrogen content, and minimizing defects like cobalt or nickel inclusions, which affect the mechanical, optical, and thermal properties of diamond materials.
Innovation Solution
A CVD method involving a synthesis environment with nitrogen at 0.4 ppm to 200 ppm and a source gas composition of hydrogen, oxygen, and carbon, where the atomic fractions of hydrogen (Hf) range from 0.40 to 0.75, carbon (Cf) from 0.15 to 0.30, and oxygen (Of) from 0.13 to 0.40, with a specific ratio of Cf:Of, allowing for increased microwave power density and pressure while minimizing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional CVD methods are used to synthesize diamond, then diamond material can be produced, but nitrogen distribution is non-uniform and defect concentrations are high
Solution Approach 1:
The patent applies parameter changes by precisely controlling the nitrogen concentration in the source gas within the range of 0.4-200 ppm, maintaining specific atomic fraction ratios of Hf (0.40-0.75), Cf (0.15-0.30), and Of (0.13-0.40), and controlling the Cf:Of ratio to achieve uniform nitrogen distribution while minimizing defects in the synthesized diamond material
Solution Approach 2:
The patent uses oxygen-containing species as an intermediary element in the source gas composition to mediate the incorporation of nitrogen into the diamond lattice, enabling uniform nitrogen distribution through the controlled interaction between oxygen and nitrogen species during the CVD synthesis process
2Productivity
If high microwave power density and pressure are applied to improve growth rate, then productivity increases, but defect concentration increases
Solution Approach 1:
The patent utilizes parameter changes by optimizing the atomic fraction ratios of hydrogen, carbon, and oxygen in the source gas, along with controlling nitrogen concentration and the Cf:Of ratio, to enable high microwave power density and pressure operation while maintaining low defect concentrations and achieving high productivity
3Productivity
If nitrogen concentration is increased to enhance growth rate, then productivity improves, but other defects increase and color quality deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling nitrogen concentration within 0.4-200 ppm and maintaining specific atomic fraction ratios of Hf, Cf, and Of to achieve enhanced growth rate while preserving high color quality through uniform nitrogen distribution and minimized defect formation
Solution Approach 2:
The patent employs oxygen-containing species as an intermediary to facilitate controlled nitrogen incorporation into the diamond lattice, enabling enhanced growth rates while maintaining high color quality through the mediating effect of oxygen on nitrogen distribution and defect formation
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 production of high-quality synthetic CVD diamond with a high concentration of single substitutional nitrogen, reduced defects, and a uniform yellow color, suitable for both electronic devices and gemstones, by controlling nitrogen distribution and minimizing other impurities.
Implementation Method 1
dissociating the source gas; wherein the source gas comprises: a) an atomic fraction of hydrogen, Hf, from 0.40 to 0.75; b) an atomic fraction of carbon, Cf, from 0.15 to 0.30; c) an atomic fraction of oxygen, Of, from 0.13 to 0.40
Implementation Method 2
A CVD method involving a synthesis environment with nitrogen at 0.4 ppm to 200 ppm and a source gas composition of hydrogen, oxygen, and carbon
Data Source
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AI summary
A chemical vapour deposition (CVD) method for synthesizing diamond material on a substrate in a synthesis environment, said method comprising: providing the substrate; providing a source gas; dissociating the source gas; and allowing homoepitaxial diamond synthesis on the substrate; wherein the synthesis environment comprises nitrogen at an atomic concentration of from about 0.4 ppm to about 50 ppm; and and wherein the source gas comprises: a) an atomic fraction of hydrogen, Hf, from about 0.40 to about 0.75; b) an atomic fraction of carbon, Cf, from about 0.15 to about 0.30; c) an atomic fraction of oxygen, Of, from about 0.13 to about 0.40; wherein Hf + Cf + Of = 1; wherein the ratio of atomic fraction of carbon to the atomic fraction of oxygen, Cf:Of, satisfies the ratio of about 0.45: 1 f:Of 2, at an atomic fraction of the total number of hydrogen, oxygen and carbon atoms present of between 0.05 and 0.40; and wherein the atomic fractions Hf, Cf and Of are fractions of the total number of hydrogen, oxygen and carbon atoms present in the source gas.