Direct correlation of microtwin distribution with growth face morphology of CVD diamond films by a novel TEM technique

Journal Article · Wed Jun 01 04:00:00 EDT 1994 · Journal of Materials Research; (United States)

DOI:https://doi.org/10.1557/JMR.1994.1552· OSTI ID:7233451

Wang, Z L ^[1]; Bentley, J; Clausing, R E; Heatherly, L; Horton, L L ^[2]

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1. Metals and Ceramics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6376 (United States) Department of Materials Science and Engineering, The University of Tennessee, Knoxville, Tennessee 37996 (United States)
2. Metals and Ceramics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6376 (United States)

A thick as-grown diamond film was examined directly by conventional transmission electron microscopy (TEM) without thinning, and the important microstructures near the growth surface were characterized. Specimen preparation for TEM involved simply fracturing the film; some of the diamond grains located on the specimen edge were thin enough to be directly examined by TEM. The 3-D topography of the diamond grains located at the intersection of the growth and the fracture surfaces was obtained using secondary electron images, so that the 2-D projected grain geometry could be derived easily to help interpret the TEM images. A diamond film grown with a [l angle]001[r angle] texture and having grains 2--3 [mu]m diameter with [l brace]001[r brace] facets parallel to the substrate and four inclined [l brace]111[r brace] facets was examined. Grains with fracture surfaces that intersected the top (001) facet, grains with fractures that intersected only [l brace]111[r brace] facets, and unfractured grains were studied. It was found that the core volume bounded by the (001) top facet and its projected column defined by orthogonal internal [l brace]110[r brace] was free from microtwins, but contained a few dislocations. The remaining volume around this core, bounded by [l brace]111[r brace] facets (or grain boundaries) and the internal [l brace]110[r brace], was filled with microtwins. The microtwins were not merely at the [l brace]111[r brace] surfaces. Our results reveal a growth mechanism in which microtwins are formed as material is added to [l brace]111[r brace] but not [l brace]001[r brace]. The formation of microtwins in CVD diamond is thus clearly associated with growth on [l brace]111[r brace] surface facets.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 7233451
• Journal Information: Journal of Materials Research; (United States), Journal Name: Journal of Materials Research; (United States) Vol. 9:6; ISSN JMREEE; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
CARBON
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
DEPOSITION
DIAMONDS
ELECTRON MICROSCOPY
ELEMENTAL MINERALS
ELEMENTS
FILMS
MICROSCOPY
MICROSTRUCTURE
MINERALS
NONMETALS
SURFACE COATING
TRANSMISSION ELECTRON MICROSCOPY
TWINNING