Skip to content

Exploring the Plasma Chemistry in Microwave Chemical Vapor Deposition of Diamond from C/H/O Gas Mixtures

Research output: Contribution to journalArticle

Standard

Exploring the Plasma Chemistry in Microwave Chemical Vapor Deposition of Diamond from C/H/O Gas Mixtures. / Kelly, Mark W.; Richley, James C.; Western, Colin M.; Ashfold, Michael N. R.; Mankelevich, Yuri A.

In: Journal of Physical Chemistry A, Vol. 116, No. 38, 27.09.2012, p. 9431-9446.

Research output: Contribution to journalArticle

Harvard

Kelly, MW, Richley, JC, Western, CM, Ashfold, MNR & Mankelevich, YA 2012, 'Exploring the Plasma Chemistry in Microwave Chemical Vapor Deposition of Diamond from C/H/O Gas Mixtures', Journal of Physical Chemistry A, vol. 116, no. 38, pp. 9431-9446. https://doi.org/10.1021/jp306190n

APA

Vancouver

Author

Kelly, Mark W. ; Richley, James C. ; Western, Colin M. ; Ashfold, Michael N. R. ; Mankelevich, Yuri A. / Exploring the Plasma Chemistry in Microwave Chemical Vapor Deposition of Diamond from C/H/O Gas Mixtures. In: Journal of Physical Chemistry A. 2012 ; Vol. 116, No. 38. pp. 9431-9446.

Bibtex

@article{f39c98c32b5147e18b380a91b38d0291,
title = "Exploring the Plasma Chemistry in Microwave Chemical Vapor Deposition of Diamond from C/H/O Gas Mixtures",
abstract = "Microwave (MW)-activated CH4/CO2/H-2 gas mixtures operating under conditions relevant to diamond chemical vapor deposition (i.e., X-C/Sigma = X-elem(C)/(X-elem(C) + X-elem(O)) approximate to 0.5, H-2 mole fraction = 0.3, pressure, p = 150 Torr, and input power, P = 1 kW) have been explored in detail by a combination of spatially resolved absorption measurements (of CH, C-2(a), and OH radicals and H(n = 2) atoms) within the hot plasma region and companion 2-dimensional modeling of the plasma. CO and H-2 are identified as the dominant species in the plasma core. The lower thermal conductivity of such a mixture (cf. the H-2-rich plasmas used in most diamond chemical vapor deposition) accounts for the finding that CH4/CO2/H-2 plasmas can yield similar maximal gas temperatures and diamond growth rates at lower input powers than traditional CH4/H-2 plasmas. The plasma chemistry and composition is seen to switch upon changing from oxygen-rich (X-C/Sigma < 0.5) to carbon-rich (X-C/Sigma > 0.5) source gas mixtures and, by comparing CH4/CO2/H-2 (X-C/Sigma = 0.5) and CO/H-2 plasmas, to be sensitive to the choice of source gas (by virtue of the different prevailing gas activation mechanisms), in contrast to C/H process gas mixtures. CH3 radicals are identified as the most abundant C1Hx [x = 0-3] species near the growing diamond surface within the process window for successful diamond growth (X-C/Sigma approximate to 0.5-0.54) identified by Bachmann et al. (Diamond Relat. Mater. 1991, 1, 1). This, and the findings of similar maximal gas temperatures (T-gas similar to 2800-3000 K) and H atom mole fractions (X(H)similar to 5-10{\%}) to those found in MW-activated C/H plasmas, points to the prevalence of similar CH3 radical based diamond growth mechanisms in both C/H and C/H/O plasmas.",
author = "Kelly, {Mark W.} and Richley, {James C.} and Western, {Colin M.} and Ashfold, {Michael N. R.} and Mankelevich, {Yuri A.}",
year = "2012",
month = "9",
day = "27",
doi = "10.1021/jp306190n",
language = "English",
volume = "116",
pages = "9431--9446",
journal = "Journal of Physical Chemistry A",
issn = "1089-5639",
publisher = "American Chemical Society",
number = "38",

}

RIS - suitable for import to EndNote

TY - JOUR

T1 - Exploring the Plasma Chemistry in Microwave Chemical Vapor Deposition of Diamond from C/H/O Gas Mixtures

AU - Kelly, Mark W.

AU - Richley, James C.

AU - Western, Colin M.

AU - Ashfold, Michael N. R.

AU - Mankelevich, Yuri A.

PY - 2012/9/27

Y1 - 2012/9/27

N2 - Microwave (MW)-activated CH4/CO2/H-2 gas mixtures operating under conditions relevant to diamond chemical vapor deposition (i.e., X-C/Sigma = X-elem(C)/(X-elem(C) + X-elem(O)) approximate to 0.5, H-2 mole fraction = 0.3, pressure, p = 150 Torr, and input power, P = 1 kW) have been explored in detail by a combination of spatially resolved absorption measurements (of CH, C-2(a), and OH radicals and H(n = 2) atoms) within the hot plasma region and companion 2-dimensional modeling of the plasma. CO and H-2 are identified as the dominant species in the plasma core. The lower thermal conductivity of such a mixture (cf. the H-2-rich plasmas used in most diamond chemical vapor deposition) accounts for the finding that CH4/CO2/H-2 plasmas can yield similar maximal gas temperatures and diamond growth rates at lower input powers than traditional CH4/H-2 plasmas. The plasma chemistry and composition is seen to switch upon changing from oxygen-rich (X-C/Sigma < 0.5) to carbon-rich (X-C/Sigma > 0.5) source gas mixtures and, by comparing CH4/CO2/H-2 (X-C/Sigma = 0.5) and CO/H-2 plasmas, to be sensitive to the choice of source gas (by virtue of the different prevailing gas activation mechanisms), in contrast to C/H process gas mixtures. CH3 radicals are identified as the most abundant C1Hx [x = 0-3] species near the growing diamond surface within the process window for successful diamond growth (X-C/Sigma approximate to 0.5-0.54) identified by Bachmann et al. (Diamond Relat. Mater. 1991, 1, 1). This, and the findings of similar maximal gas temperatures (T-gas similar to 2800-3000 K) and H atom mole fractions (X(H)similar to 5-10%) to those found in MW-activated C/H plasmas, points to the prevalence of similar CH3 radical based diamond growth mechanisms in both C/H and C/H/O plasmas.

AB - Microwave (MW)-activated CH4/CO2/H-2 gas mixtures operating under conditions relevant to diamond chemical vapor deposition (i.e., X-C/Sigma = X-elem(C)/(X-elem(C) + X-elem(O)) approximate to 0.5, H-2 mole fraction = 0.3, pressure, p = 150 Torr, and input power, P = 1 kW) have been explored in detail by a combination of spatially resolved absorption measurements (of CH, C-2(a), and OH radicals and H(n = 2) atoms) within the hot plasma region and companion 2-dimensional modeling of the plasma. CO and H-2 are identified as the dominant species in the plasma core. The lower thermal conductivity of such a mixture (cf. the H-2-rich plasmas used in most diamond chemical vapor deposition) accounts for the finding that CH4/CO2/H-2 plasmas can yield similar maximal gas temperatures and diamond growth rates at lower input powers than traditional CH4/H-2 plasmas. The plasma chemistry and composition is seen to switch upon changing from oxygen-rich (X-C/Sigma < 0.5) to carbon-rich (X-C/Sigma > 0.5) source gas mixtures and, by comparing CH4/CO2/H-2 (X-C/Sigma = 0.5) and CO/H-2 plasmas, to be sensitive to the choice of source gas (by virtue of the different prevailing gas activation mechanisms), in contrast to C/H process gas mixtures. CH3 radicals are identified as the most abundant C1Hx [x = 0-3] species near the growing diamond surface within the process window for successful diamond growth (X-C/Sigma approximate to 0.5-0.54) identified by Bachmann et al. (Diamond Relat. Mater. 1991, 1, 1). This, and the findings of similar maximal gas temperatures (T-gas similar to 2800-3000 K) and H atom mole fractions (X(H)similar to 5-10%) to those found in MW-activated C/H plasmas, points to the prevalence of similar CH3 radical based diamond growth mechanisms in both C/H and C/H/O plasmas.

U2 - 10.1021/jp306190n

DO - 10.1021/jp306190n

M3 - Article

C2 - 22924542

VL - 116

SP - 9431

EP - 9446

JO - Journal of Physical Chemistry A

JF - Journal of Physical Chemistry A

SN - 1089-5639

IS - 38

ER -