High-temperature morphological evolution of lithographically introduced cavities in silicon carbide
Internal cavities of controlled geometry and crystallography were introduced in 6H silicon carbide single crystals by combining lithographic methods, ion beam etching, and solid-state diffusion bonding. The morphological evolution of these internal cavities (negative crystals) in response to anneals of up to 128 h duration at 1900 degrees C was examined using optical microscopy. Surface energy anisotropy and faceting have a strong influence on both the geometric and kinetic characteristics of evolution. Decomposition of 12{bar 1}0 cavity edges into 101{bar 0} facets was observed after 16 h anneals, indicating that 12{bar 1}0 faces are not components of the Wulff shape. The shape evolution kinetics of penny-shaped cavities were also investigated. Experimentally observed evolution rates decreased much more rapidly with those predicted by a model in which surface diffusion is assumed to be rate-limiting. This suggests that the development of facets, and the associated loss of ledges and terraces during the initial stages of evolution results in an evolution process limited by the nucleation rate of attachment/detachment sites (ledges) on the facets.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director, Office of Science. Office of Basic Energy Studies (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 787096
- Report Number(s):
- LBNL-46789; JACTAW; R&D Project: 512701; TRN: AH200134%%32
- Journal Information:
- Journal of the American Ceramic Society, Vol. 84, Issue 5; Other Information: Journal Publication Date: May 2001; PBD: 1 Dec 2000; ISSN 0002-7820
- Country of Publication:
- United States
- Language:
- English
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