What [plasma used for growing] diamond can shine like flame?

Ashfold, Michael N. R.; Mahoney, Edward J D; Mushtaq, Sohail; Truscott, Benjamin S.; Mankelevich, Yuri A.

doi:10.1039/c7cc05568d

Cited by 15 publications

(22 citation statements)

References 123 publications

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“…Much of this complexity is now understood, however, through a combination of spatially resolved in-situ spectroscopic studies of the gas-phase composition as functions of process conditions and complementary plasma modelling. [31][32][33][58][59][60][61][62][63][64][65][66][67][68] Radicals containing just one carbon atom are recognised as key to CVD diamond growth and, of these, the methyl (CH3) radical is generally the most abundant in the immediate vicinity of the growing diamond surface (where Tgas is little more than half that in the plasma core). 69 As noted above, CVD diamond typically presents two principal low-index surfacesthe C (111) and C(100) surfacesand, given the high H-atom flux in the CVD environment, we here focus attention on the fully hydrogenated surfaces.…”

Section: The Cvd Growth Mechanismmentioning

confidence: 99%

Nitrogen in Diamond

et al. 2020

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Nitrogen is ubiquitous in both natural and laboratory-grown diamond, but the number and nature of the nitrogen-containing defects can have a profound effect on the diamond material and its properties. An ever-growing fraction of the supply of diamond appearing on the world market is now lab-grown. Here, we survey recent progress in two complementary diamond synthesis methodshigh pressure high temperature (HPHT) growth and chemical vapour deposition (CVD), how each is allowing ever more precise control of nitrogen incorporation in the resulting diamond, and how the diamond produced by either method can be further processed (e.g. by implantation and/or annealing) to achieve a particular outcome or property. The burgeoning availability of diamond samples grown under well-defined conditions has also enabled huge advances in the characterization and understanding of nitrogen-containing defects in diamondalone, and in association with vacancies, hydrogen and transition metal atoms. Amongst these, the negatively charged nitrogen-vacancy (NV −) defect in diamond is attracting particular current interest on account of the many new and exciting opportunities it offers for, e.g., quantum technologies, nanoscale magnetometry and biosensing. 2 Laboratory Based Synthesis of Diamond and Nitrogen-Containing Diamond 2.1 High Pressure High Temperature (HPHT) Methods. Nature was the inspiration for the HPHT method, by which diamond growth was demonstrated by Swedish company ASEA in 1953 (though not reported at that time) and subsequently by US company General Electric in 1955. 14 , 15 Most present-day HPHT synthesis exploits the temperature-gradient growth (TGG) method developed later in that decade. 16 However, it took many further years before the design and control of HPHT reactors yielded diamonds of

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Section: The Cvd Growth Mechanismmentioning

confidence: 99%

Nitrogen in Diamond

et al. 2020

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“…The available experimental data do not give us enough evidence for a detailed comment on the atomic structure of the carbon nanoclusters. They could be heavy C n H z species formed in the cooler outer regions of plasma [46][47][48], or solid carbon particles [49,50] which are not thermally desorbed or etched by atomic hydrogen. Alternatively, these carbon nanoclusters could be nanoscopic regions of non-diamond formations on the diamond surface.…”

Section: Carbon Nanoclustersmentioning

confidence: 99%

Nitrogen-doped CVD diamond: Nitrogen concentration, color and internal stress

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et al. 2020

Diamond and Related Materials

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Single crystal CVD diamond has been grown on (100)-oriented CVD diamond seed in six layers to a total thickness of 4.3 mm, each layer being grown in gas with increasing concentration of nitrogen. The nitrogen doping efficiency, distribution of color and internal stress have been studied by SIMS, optical absorption, Raman spectroscopy and birefringence imaging. It is shown that nitrogen doping is very non-uniform. This non-uniformity is explained by the terraced growth of CVD diamond. The color of the nitrogen-doped diamond is grayish-brown with color intensity gradually increasing with nitrogen concentration. The absorption spectra are analyzed in terms of two continua representing brown and gray color components. The brown absorption continuum exponentially rises towards short wavelength. Its intensity correlates with the concentration of nitrogen C-defects. Small vacancy clusters are discussed as the defects responsible for the brown absorption continuum. The gray absorption continuum has weak and almost linear spectral dependence through the near infrared and visible spectral range. It is ascribed to carbon nanoclusters which may form in plasma and get trapped into growing diamond. It is suggested that Mie light scattering on the carbon nanoclusters substantially contributes to the gray absorption continuum and determines its weak spectral dependence. A Raman line at a wavenumber of 1550 cm −1 is described as a characteristic feature of the carbon nanoclusters. The striation pattern of brown/gray color follows the pattern of anomalous birefringence suggesting that the vacancy clusters and carbon inclusions are the main cause of internal stress in CVD diamond. A conclusion is made that high perfection of seed surface at microscale is not a required condition for growth of low-stress, low-inclusion single crystal CVD diamond. Crystallographic order at macroscale is more important requirement for the seed surface.

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“…The gas phase and plasma chemistry that underpins diamond CVD is by now quite well understood, through a combination of experiments (e.g. laser absorption and/or optical emission spectroscopy measurements [6][7][8][9] of the densities of selected gas phase species in their ground and/or excited states) and complementary plasma modelling. [6][7][8]10 Silicon is a common trace element in CVD-grown diamond, [11][12][13][14][15][16][17][18] arising either adventitiouslyby etching from the silicon substrate on which diamond is commonly grown or from silica windows or walls of the MW reactor during hydrogen termination and/or growth of diamondor by design if, for example, SiH4 is added to the process gas mixture.…”

Section: Introductionmentioning

confidence: 99%

Optical Emission Imaging and Modeling Investigations of Microwave-Activated SiH₄/H₂ and SiH₄/CH₄/H₂ Plasmas

et al. 2020

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Silicon is a known trace contaminant in diamond grown by chemical vapor deposition (CVD) methods.Deliberately Si-doped diamond is currently attracting great interest because of the attractive optical properties of the negatively charged silicon-vacancy (SiV − ) defect. This work reports in-depth studies of microwave activated H2 plasmas containing trace (10-100 ppm) amounts of SiH4, with and without a few % of CH4, operating at pressures and powers relevant for contemporary diamond CVD, using a combination of experiment (spatially resolved optical emission (OE) imaging) and two-dimensional

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What [plasma used for growing] diamond can shine like flame?

Abstract: The gas-phase chemistry underpinning the chemical vapour deposition of diamond from microwave-activated methane/hydrogen plasmas is surveyed.

Cited by 15 publications

References 123 publications

Nitrogen in Diamond

Nitrogen in Diamond

Nitrogen-doped CVD diamond: Nitrogen concentration, color and internal stress

Optical Emission Imaging and Modeling Investigations of Microwave-Activated SiH₄/H₂ and SiH₄/CH₄/H₂ Plasmas

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What [plasma used for growing] diamond can shine like flame?

Abstract: The gas-phase chemistry underpinning the chemical vapour deposition of diamond from microwave-activated methane/hydrogen plasmas is surveyed.

Cited by 15 publications

References 123 publications

Nitrogen in Diamond

Nitrogen in Diamond

Nitrogen-doped CVD diamond: Nitrogen concentration, color and internal stress

Optical Emission Imaging and Modeling Investigations of Microwave-Activated SiH4/H2 and SiH4/CH4/H2 Plasmas

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Optical Emission Imaging and Modeling Investigations of Microwave-Activated SiH₄/H₂ and SiH₄/CH₄/H₂ Plasmas