Microstructure of ultrananocrystalline diamond films grown by microwave Ar--CH{sub 4} plasma chemical vapor deposition with or without added H{sub 2}

Journal Article · Sun Jul 01 04:00:00 EDT 2001 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1377301· OSTI ID:40277599

Jiao, S; Sumant, A; Kirk, M A; Gruen, D M; Krauss, A R; Auciello, O

Ultrananocrystalline diamond (UNCD) films, grown using microwave plasma-enhanced chemical vapor deposition with gas mixtures of Ar--1%CH{sub 4} or Ar--1%CH{sub 4}--5%H{sub 2}, have been examined with transmission electron microscopy (TEM). The films consist of equiaxed nanograins (2--10 nm in diameter) and elongated twinned dendritic grains. The area occupied by dendritic grains increases with the addition of H{sub 2}. High resolution electron microscopy shows no evidence of an amorphous phase at grain boundaries, which are typically one or two atomic layer thick (0.2--0.4 nm). Cross-section TEM reveals a noncolumnar structure of the films. The initial nucleation of diamond occurs directly on the Si substrate when H{sub 2} is present in the plasma. For the case of UNCD growth from a plasma without addition of H{sub 2}, the initial nucleation occurs on an amorphous carbon layer about 10--15 nm thick directly grown on the Si substrate. This result indicates that hydrogen plays a critical role in determining the nucleation interface between the UNCD films and the Si substrate. The relation between diamond nuclei and Si is primarily random and occasionally epitaxial.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• Sponsoring Organization: (US)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 40277599
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 1 Vol. 90; ISSN 0021-8979
• Publisher: The American Physical Society
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL VAPOR DEPOSITION
DIAMONDS
ELECTRON MICROSCOPY
GRAIN BOUNDARIES
MICROSTRUCTURE
PLASMA
TRANSMISSION ELECTRON MICROSCOPY