Methods of fabricating synthetic diamond materials using microwave plasma activated chemical vapour deposition techniques and products obtained using said methods

Abstract

A method of fabricating synthetic diamond material using a microwave plasma activated chemical vapour deposition technique is provided which utilizes high and uniform microwave power densities applied over large areas and for extended periods of time. Products fabricated using such a synthesis technique are described including a single crystal CVD diamond layer which has a large area and a low nitrogen concentration, and a high purity, fast growth rate single crystal CVD diamond material.

Description

FIELD OF INVENTION[0001]The present invention relates to methods of fabricating synthetic diamond materials using microwave plasma active chemical vapour deposition techniques and products obtained using said methods. Products comprising very high purity single crystal synthetic diamond material are described and method of manufacturing the same at increased growth rates while retaining exceptional electronic, optical, thermal, and / or quantum coherence characteristics. Such a high purity single crystal CVD diamond material is useful in a range of applications including optical components, electronic components, radiation detectors, and quantum sensing and information processing devices. Certain further implementations relate to more economic methods for fabricating lower purity synthetic diamond products. Yet further implementations relate to synthesis of large area synthetic diamond wafers with improved electronic, optical, thermal, and / or quantum coherence characteristics.BACKGROU...

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Benefits of technology

[0034]Following on from the work described in the aforementioned documents, the present applicant has found that using suitable microwave plasma activated CVD reactor hardware and CVD diamond synthesis methodology it is possible to achieve high

Problems solved by technology

Such a theoretically perfect diamond lattice is thermodynamically impossible to attain.

In reality, it is practically difficult to even approach a level of perfection which would be possible to achieve in theory when taking into account thermodynamic considerations.

As such, it should be apparent that all diamond materials contain a significant number of defects.

Such defects may come in the form of impurities.

Additionally, defects within diamond materials also include crystallographic deviations from the perfect diamond lattice structure in the form of point defects such as vacancies and interstitials and extended defects such as various forms of dislocation defects.

Defects within diamond materials significantly alter the properties of the materials.

Furthermore, the nature of the substrate material and the growth conditions affect the type and distribution of defects incorporated into the CVD synthetic diamond material during growth.

However, in such applications impurities can interact with quantum spin defects within the diamond lattice structure reducing their decoherence time and thus reducing their sensitivity and/or reducing the time during which quantum processing applications can be performed.

Nitrogen is one of the most important dopants in CVD diamond material synthesis as it has been found that providing nitrogen in the CVD process gas increases the growth rate of the material and can also affect the formation of crystallographic defects such as dislocations.

A problem with synthesizing low defect, high purity single crystal CVD synthetic diamond material is that such material has a very low growth rate and is thus time consuming and expensive to manufacture.

Furthermore, due to the extended time periods required to obtain a desired thickness of such material at low growth rates, the growth process must be very precisely controlled over extended time periods and this can be difficult to achieve in practice resulting in reduced yields.

However, while single crystal CVD synthetic diamond material according to this process is suitable for many optical applications, the concentration of nitrogen incorporated into the material is such that the material is not ideally suited for certain high-end optical a

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