Enhancement of the nucleation of smooth and dense nanocrystalline diamond films by using molybdenum seed layers

Journal Article · Mon Nov 15 00:00:00 EST 2010 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3506525· OSTI ID:21537932

Buijnsters, J G ^[1]; Vazquez, L ^[2]; Meulen, J J. ter; Celis, J P ^[1]

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1. Department of Metallurgy and Materials Engineering, Katholieke Universiteit Leuven, Kasteelpark Arenberg 44, B-3001 Leuven (Belgium)
2. Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Cantoblanco, C/Sor Juana Ines de la Cruz 3, 28049 Madrid (Spain)

A method for the nucleation enhancement of nanocrystalline diamond (NCD) films on silicon substrates at low temperature is discussed. A sputter deposition of a Mo seed layer with thickness 50 nm on Si substrates was applied followed by an ultrasonic seeding step with nanosized detonation diamond powders. Hot-filament chemical vapor deposition (HF-CVD) was used to nucleate and grow NCD films on substrates heated up at 550 deg. C. The nucleation of diamond and the early stages of NCD film formation were investigated at different methane percentages in methane/hydrogen gas mixtures by atomic force microscopy, micro-Raman spectroscopy, scanning electron microscopy, and grazing incidence x-ray analyses in order to gain specific insight in the nucleation process of NCD films. The nucleation kinetics of diamond on the Mo-coated Si substrates was found to be up to ten times higher than on blank Si substrates. The enhancement of the nucleation of diamond on thin Mo interlayers results from two effects, namely, (a) the nanometer rough Mo surface shows an improved embedding of ultrasonically introduced nanosized diamond seeds that act as starting points for the diamond nucleation during HF-CVD and (b) the rapid carbonization of the Mo surface causes the formation of Mo{sub 2}C onto which diamond easily nucleates. The diamond nucleation density progressively increases at increasing methane percentages and is about 5x10{sup 10} cm{sup -2} at 4.0% methane. The improved nucleation kinetics of diamond on Mo interlayers facilitates the rapid formation of NCD films possessing a very low surface roughness down to {approx}6 nm, and allows a submicron thickness control.

• OSTI ID: 21537932
• Journal Information: Journal of Applied Physics, Vol. 108, Issue 10; Other Information: DOI: 10.1063/1.3506525; (c) 2010 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ATOMIC FORCE MICROSCOPY
CHEMICAL VAPOR DEPOSITION
CRYSTALS
DIAMONDS
FILAMENTS
GRAZING INCIDENCE TOMOGRAPHY
LAYERS
MOLYBDENUM
MOLYBDENUM CARBIDES
NANOSTRUCTURES
NUCLEATION
POWDERS
RAMAN SPECTRA
RAMAN SPECTROSCOPY
SCANNING ELECTRON MICROSCOPY
SILICON
SPUTTERING
SUBSTRATES
SURFACES
THIN FILMS
CARBIDES
CARBON
CARBON COMPOUNDS
CHEMICAL COATING
DEPOSITION
DIAGNOSTIC TECHNIQUES
ELECTRON MICROSCOPY
ELEMENTS
FILMS
LASER SPECTROSCOPY
METALS
MICROSCOPY
MINERALS
MOLYBDENUM COMPOUNDS
NONMETALS
REFRACTORY METAL COMPOUNDS
REFRACTORY METALS
SEMIMETALS
SPECTRA
SPECTROSCOPY
SURFACE COATING
TOMOGRAPHY
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS