Substrate Stage Assembly for Inclusion-Free Diamond Growth
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Solution Overview
Problem
Existing methods for growing mono-crystalline diamonds using microwave plasma chemical vapor deposition often incorporate impurities due to inefficient gas decomposition and thermal decomposition of methane, leading to graphitic and non-graphitic inclusions, which compromise the quality and purity of the diamonds.
Innovation Solution
A substrate stage assembly is designed to provide a uniform microwave electric field and control the temperature, reducing un-reacted methane and preventing thermal decomposition, thereby increasing the concentration of CH3+ ions and minimizing carbon soot formation, ensuring the growth of inclusion-free diamonds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If microwave plasma chemical vapour deposition is used to grow mono-crystalline diamonds, then diamond growth is achieved, but impurities are incorporated due to inefficient gas decomposition
Solution Approach 1:
The single deposition chamber is divided into multiple chambers arranged in series. The gas flow is segmented through multiple stages, with each chamber performing a specific function (diamond growth, gas purification, gas reuse). This segmentation allows efficient decomposition of gases across multiple stages, reducing impurity incorporation while maintaining diamond growth productivity.
Solution Approach 2:
Intermediate chambers are introduced between the diamond growth chamber and the exhaust system. These intermediate chambers act as mediators to purify the gas composition by removing impurities before the gas is either reused or exhausted, thereby reducing the harmful effect of impurity incorporation in the diamond structure.
2Quantity of substance
If thermal decomposition of methane occurs in the chamber, then carbon supply is maintained, but graphitic and non-graphitic inclusions are formed
Solution Approach 1:
Different chambers are designed with different local conditions optimized for specific functions. The diamond growth chamber maintains conditions suitable for pure diamond formation, while subsequent chambers provide environments for gas purification. This local quality differentiation ensures carbon supply for growth without introducing graphitic inclusions from thermal decomposition.
Solution Approach 2:
The un-reacted methane and decomposition products that would normally be harmful are converted into beneficial resources. The purification chambers remove impurities from the exhaust gas, and the purified gas is reused in the diamond growth chamber, transforming potential contaminants into clean carbon sources for diamond growth.
3Object-affected harmful factors
If exhaust gases are released to atmosphere, then contamination is avoided, but gas composition is not utilized for further diamond growth
Solution Approach 1:
Instead of simply discarding the exhaust gases to the atmosphere, the system recovers useful components from the exhaust stream. The purification chambers remove impurities from the exhaust gas, and the cleaned gas is reused in the diamond growth process, thereby recovering valuable carbon-containing species while still avoiding contamination from atmospheric reintroduction.
Solution Approach 2:
The gas flow continues through multiple chambers in series, maintaining continuous useful action. The gas that exits the diamond growth chamber continues to flow through purification and reuse chambers, extending its useful life and maintaining continuous diamond growth capability without interruption or waste.
4Ease of manufacture
If poly-crystalline diamond is produced, then production is simplified, but grain boundaries and defects reduce thermal conductivity
Solution Approach 1:
The use of multiple chambers in series segments the manufacturing process into distinct functional stages. This enables precise control of growth conditions in each chamber, allowing mono-crystalline diamond formation with superior properties while maintaining manufacturing efficiency through the modular chamber design.
Solution Approach 2:
Different physical and chemical parameters are optimized in different chambers along the gas flow path. By changing parameters such as temperature, pressure, and gas composition across the series of chambers, the process achieves high-quality mono-crystalline diamond growth with excellent thermal conductivity while maintaining production efficiency.
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 solution enables the production of high-quality, inclusion-free mono-crystalline diamonds by maintaining a uniform electric field and reducing peripheral temperature, resulting in improved purity and clarity, and reducing manufacturing costs through gas reuse and efficient diamond growth.
Implementation Method 1
The gases are decomposed into various ionic forms and radicals using an intense microwave electric field at a frequency of 2.45 GHz
Implementation Method 2
microwave plasma chemical vapour deposition process
Implementation Method 3
thermal decomposition of methane, leading to graphitic and non-graphitic inclusions
Data Source
AI summary
An apparatus for growing diamonds, the apparatus comprising: one or more chambers, each chamber is in fluid connection with one or more other chambers, each chamber comprising one or more substrate stage assembly within the chamber to support a substrate stage having a plurality of diamond seeds disposed thereon.