- Composition of tungsten silicide films deposited by dichlorosilane reduction of tungsten hexafluoride
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The composition profile of tungsten silicide (WSix) films deposited by low-pressure chemical vapor deposition employing dichlorosilane (DCS) reduction of tungsten hexafluoride (WF6) is studied. Diffusion is the reaction rate-limiting process at chuck temperatures above 550°C and uniform in-depth composition profiles can be obtained. Below 550°C, however, the in-depth composition profile is not uniform for the surface reaction rate-limiting process. Tungsten-rich layers with a Si composition, x, of 1.5, are initially deposited due to the reduction of WF6 by the Si surface. This layer is amorphous or microcrystalline. Thereafter, the silicon content of the film increases with increasing thickness and a uniform composition profile is obtained as determined by the DCS/WF6 flow rate ratio in the chemical reaction. Chemical vapor-deposited tungsten silicide (WSix) films have been extensively used as polycide gate and interconnections for very large-scale integrated circuits.
- Hara,Miyamoto,Hagiwara,Bromley,Harshbarger
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p. 2955 - 2959
(2008/10/08)
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