Use of novel methods for the investigation of the boron distribution in CVD diamond

Steeds, J. W.; Gilmore, A.; Charles, SJ; Heard, Peter J; Howarth, B; Butler, James E.

doi:10.1016/s1359-6454(99)00262-1

Cited by 35 publications

(11 citation statements)

References 19 publications

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“…It may be introduced into the material during deposition and a wide range of boron concentrations have been achieved, up to a few percent. However, the amount incorporated depends on the particular growth sector. − For the case of polycrystalline diamond films obtained by chemical vapor deposition (CVD) techniques, there are a number of papers describing the spatially inhomogeneous distribution of boron. For example, the dopant concentration in the 〈111〉 growth sector is approximately 1 order of magnitude higher than that in the 〈100〉 sector. , It may be also supposed that boron can aggregate in the grain boundaries of polycrystalline films, and in such a case, these dopant atoms will not function electronically in terms of providing charge carriers.…”

Section: Introductionmentioning

confidence: 99%

A Confocal Raman Imaging Study of an Optically Transparent Boron-Doped Diamond Electrode

et al. 2002

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International audienceConfocal micro-Raman imaging was used to investigate the structural and, to some extent, the chemical inhomogeneities that exist in a high-quality, free-standing, polished, optically transparent boron-doped chemical-vapor-deposition (CVD) diamond disk. A number of boron-related Raman lines centered at about 610, 925, 1045, 1375, and 1470 cm^-1 were evidenced and found to vary from one region of the disk to another. These lines have previously been reported in the literature for other boron-doped crystals or films obtained using completely different growth conditions. Even if their origin is still somewhat uncertain, their presence enabled the construction of spatial maps of the boron signal intensity over the surface. It was confirmed that boron is incorporated into CVD diamond with significant inhomogeneities. In most cases, the boron signal intensity tracked the structure of the grains. The high quality of the disk also allowed a detailed analysis of the grain boundaries to be made. However, a unique description of these grain boundaries in terms of their microstructure and chemical composition could not be developed. There is some evidence that nondiamond phases are incorporated into the grain boundaries, but their Raman signature is quite distinct from that usually reported. Another remarkable feature of this disk is that it is nearly photoluminescence-free. Photoluminescence, as excited by the 514.5 or 457.9 nm lines of an argon ion laser, was only detected within some of the nondiamond amorphous carbon-rich grain boundaries. The low photoluminescence background was also a common feature of a heavily boron-doped, polycrystalline film deposited on silicon, another sample that was also examined in this work for comparison. Despite its high quality, the optically transparent disk is far from being stress-free. Localized stress variations were observed. The strained regions are not systematically associated with the incorporation of nondiamond carbon. Grain boundaries and, most probably, planar defects have been identified as the stress sources. However, it remains difficult to explain the large compressive stress observed for some of the crystals

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Section: Introductionmentioning

confidence: 99%

A Confocal Raman Imaging Study of an Optically Transparent Boron-Doped Diamond Electrode

et al. 2002

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“…B offers more of a challenge since B-doped diamond is only weakly luminescent and is associated with a broad green luminescence band (Collins et al, 1990) We have now established several new ways to study the level of B incorporation into CVD diamond. One of these involves the use of an in-house constructed liquid Ga source magnetic sector secondary ion microscope (Steeds et al, 1999c). For samples with B concentrations ∼10 20 cm −3 , B ion images show the variation of B from one region to another very clearly: variations of up to a factor of 8 in B concentration are illustrated in Figure 7.…”

Section: Dopant and Impurity Distributionsmentioning

confidence: 99%

“…At B concentrations of about 10 19 cm −3 and above the form of the Raman longitudinal-optic phonon line-profiles change because of a Fano resonance between the electronic and phonon states. This effect may also be used to map out the local changes of B concentration (Steeds et al, 1999c). Now it also seems likely that sharp ZPLs induced in B-doped samples by electron irradiation may also be used for this purpose.…”

Section: Dopant and Impurity Distributionsmentioning

confidence: 99%

Extended and Point Defects in Diamond Studied with the Aid of Various Forms of Microscopy

Steeds

Charles

Gilmore

et al. 2000

Microsc. Microanal.

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It is shown that star disclinations can be a significant source of stress in chemical vapor deposited (CVD) diamond. This purely geometrical origin contrasts with other sources of stress that have been proposed previously. The effectiveness is demonstrated of the use of electron irradiation using a transmission electron microscope (TEM) to displace atoms from their equilibrium sites to investigate intrinsic defects and impurities in CVD diamond. After irradiation, the samples are studied by low temperature photoluminescence microscopy using UV or blue laser illumination. Results are given that are interpreted as arising from isolated <100> split self-interstitials and positively charged single vacancies. Negatively charged single vacancies can also be revealed by this technique. Nitrogen and boron impurities may also be studied similarly. In addition, a newly developed liquid gallium source scanned ion beam mass spectrometry (SIMS) instrument has been used to map out the B distribution in B doped CVD diamond specimens. The results are supported by micro-Raman spectroscopy.

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“…Changes of the Fano profile can be used to measure the local doping level and map out changes of boron concentration. Alternatively, SIMS is also a technique sensitive to small B concentrations and so the same task can be performed by B SIMS images [5].…”

Section: Point Defect and Dopant Distributionsmentioning

confidence: 99%

Extended and Point Defects in Diamond Studied With the Aid of Various Forms of Microscopy

Steeds

1999

Microsc Microanal

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IntroductionThere is considerable interest in CVD diamond layers for a wide variety of applications. Growth of high quality and phase pure material is now achieved in a number of laboratories but it remains to optimize the growth process for particular applications so that physical properties approaching or even exceeding those of the best natural diamond can be achieved. We have found that the combined use of a wide range of different microscopies is effective in the process of refinement.Diamond quality and phase purityRaman spectroscopy is widely used to investigate the phase purity of diamond layers. Infra-red Raman is particularly sensitive to the presence of traces of non-diamond carbon in diamond while ultra-violet Raman reveals the presence of traces of diamond carbon in layers that largely are not sp bonded. For thick rather perfect layers confocal micro-Raman mapping is a convenient method for revealing the locations of non-diamond regions.

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Use of novel methods for the investigation of the boron distribution in CVD diamond

Cited by 35 publications

References 19 publications

A Confocal Raman Imaging Study of an Optically Transparent Boron-Doped Diamond Electrode

A Confocal Raman Imaging Study of an Optically Transparent Boron-Doped Diamond Electrode

Extended and Point Defects in Diamond Studied with the Aid of Various Forms of Microscopy

Extended and Point Defects in Diamond Studied With the Aid of Various Forms of Microscopy

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