CVD Diamond Color Control via Boron Nitrogen Compensation
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Solution Overview
Problem
The synthesis of high-color single crystal CVD diamond is hindered by the detrimental effects of nitrogen in the CVD synthesis atmosphere, which leads to undesirable yellow/brown colors and increased costs due to the need for stringent nitrogen removal processes.
Innovation Solution
Introducing a controlled amount of boron into the CVD diamond synthesis atmosphere to suppress the roughening effect of nitrogen, thereby maintaining a smooth growth surface and reducing the incorporation of defects that degrade the diamond's optical and electronic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If nitrogen is removed from the CVD synthesis atmosphere to produce high color diamond, then the diamond color quality improves, but the process complexity and cost increase
Solution Approach 1:
The patent converts the harmful effect of nitrogen (which causes yellow/brown coloration) into a beneficial outcome by introducing boron as a compensating impurity. The boron suppresses the roughening effect of nitrogen on the growth surface and compensates for the color degradation, allowing nitrogen to remain in the synthesis atmosphere without compromising diamond color quality, thereby eliminating the need for complex nitrogen removal processes
Solution Approach 2:
Boron acts as an intermediary element that mediates between the harmful nitrogen and the desired diamond quality. The boron atoms incorporate into the diamond lattice and growth surface, where they suppress nitrogen-induced roughening and compensate for color degradation, enabling the coexistence of nitrogen and high color quality without requiring nitrogen removal
2Ease of manufacture
If nitrogen is present in the CVD synthesis atmosphere, then the synthesis process is simplified and costs are reduced, but the diamond develops undesirable yellow/brown colors
Solution Approach 1:
The patent converts the harmful coloration effect of nitrogen into a beneficial situation by adding boron, which suppresses nitrogen's roughening effect on the growth surface and compensates for color degradation. This allows the synthesis process to remain simple with nitrogen present in the atmosphere, while the diamond maintains high color quality
Solution Approach 2:
The patent changes the impurity composition parameters by introducing boron alongside nitrogen. This parameter change transforms the system from one where nitrogen alone degrades color to one where boron-nitrogen interaction suppresses roughening and compensates for color loss, enabling simple synthesis with high color output
3Ease of manufacture
If nitrogen is present in the CVD synthesis atmosphere, then the synthesis process is simplified, but the growth surface roughens and defect incorporation increases
Solution Approach 1:
The patent converts nitrogen's harmful roughening effect into a beneficial outcome by introducing boron, which suppresses the roughening. This allows the synthesis process to remain simple with nitrogen present, while the growth surface maintains smoothness and defect incorporation is reduced
Solution Approach 2:
Boron serves as an intermediary that suppresses nitrogen's roughening effect on the growth surface. The boron atoms interact with nitrogen at the surface, preventing nitrogen-induced roughening and maintaining surface smoothness, thereby enabling simple synthesis processes without sacrificing manufacturing precision
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 method allows for the production of single crystal CVD diamond with high color, even in the presence of significant nitrogen, simplifying the synthesis process and reducing costs by eliminating the need for extensive nitrogen removal, while maintaining high optical and electronic properties.
Implementation Method 1
Methods of depositing material such as diamond on a substrate by CVD are now well established
Implementation Method 2
Dissociation of the source gas mixture is brought about by an energy source such as microwaves, RF (radio frequency) energy, a flame, a hot filament or jet based technique and the reactive gas species so produced are allowed to deposit onto a substrate and form diamond
Data Source
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AI summary
A method for producing a CVD diamond having a high colour, which is suitable for optical applications, for example. The method includes adding a gaseous source comprising a second impurity atom type to counter the detrimental effect on colour caused by the presence in the CVD synthesis atmosphere of a first impurity atom type. The described method applies to the production of both single crystal diamond and polycrystalline diamond.