Morphological and compositional evolution of Pt-Si intermetallic thin films prepared by the activated adsorption of SiH{sub 4} on Pt(111)
- Univ. of Illinois, Urbana, IL (United States)
The authors have investigated using scanning tunneling microscopy (STM) and Auger electron spectroscopy (AES) the growth and structural evolution of Pt-Si intermetallic phases formed via a chemical vapor deposition (CVD) mediated process. The Pt silicide thin films were prepared though the exposure of a Pt(111) crystal to silane (SiH{sub 4}) followed by various annealing treatments. The deposition of Si via the decomposition of silane at room temperature preferentially forms clusters at step edges that avoid the centers of Pt terraces. The sizes and coverages of the clusters increases with silane exposure. The clusters are of intermetallic character (composed of both Si and Pt) and coarsen to give cluster heights much larger than a Pt(111) step height. These observations implicitly establish that Si interdiffusion in the near-surface region is weakly activated. Studies performed as a function of the silane exposure and annealing temperature reveal a complicated phase behavior that incorporates seven separate atomically ordered phases in addition to large-scale surface features such as three-dimensional islands. Growth and degradation mechanisms have been constructed, and the phenomena observed are contrasted with standard kinetic models based on sequential phase growth.
- Sponsoring Organization:
- USDOE, Washington, DC (United States); Illinois Univ., Urbana, IL (United States); National Science Foundation, Washington, DC (United States)
- DOE Contract Number:
- FG02-91ER45439
- OSTI ID:
- 347511
- Journal Information:
- Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Vol. 103, Issue 16; Other Information: PBD: 22 Apr 1999
- Country of Publication:
- United States
- Language:
- English
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