Uniform tungsten silicide films produced by chemical vapor deposition
AssigneeApplied Materials, Inc.
InventorsSusan G. Telford, Meng C. Tseng, Michio Aruga, Moshe Eizenberg
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Abstract
A tungsten silicide film is deposited from WF.sub.6 and SiCl.sub.2 H.sub.2 onto a substrate so that the tungsten to silicon ratio is substantially uniform through the thickness of the WSi.sub.x film, and the WSi.sub.x film is substantially free of fluorine. The film can be deposited by a multi-stage process where the pressure in the chamber is varied, or by a high temperature, high pressure deposition process in a plasma cleaned deposition chamber. Preferably the SiCl.sub.2 H.sub.2 and the WF.sub.6 are mixed upstream of the deposition chamber. A seeding gas can be added to the process gases.
Claims11
A chemical vapor deposition process for depositing a substantially uniform, substantially fluorine-free layer of WSi.sub.x on a substrate, the process comprising the steps of:
- (a) placing a substrate in a deposition zone;
- (b) during a first stage, (i) introducing a first process gas comprising dichlorosilane and tungsten hexa-fluoride into the deposition zone, (ii) regulating the flow of the first process gas to maintain the pressure in the deposition zone at a first higher pressure of at least 1 Torr, and (iii) heating the substrate to a sufficiently high temperature to deposit WSi.sub.x directly on the substrate;
- and
- (c) during a second stage, (i) introducing a second process gas comprising dichlorosilane and tungsten hexa-fluoride into the deposition zone, (ii) regulating the flow of the second process gas to lower the pressure in the deposition zone to a second lower pressure of at least 0.5 Torr, the second lower pressure being at least 0.5 Torr less than the first higher pressure, so that x is substantially uniform through the thickness of the WSi.sub.x layer, and (iii) continuing to heat the substrate to a sufficiently high temperature to deposit WSi.sub.x on the substrate.
Dependencies are inferred from the claim text.