SIMPLIFIED PRODUCTION PROCESS OF WSi2 BY CVD
Original Publication Date: 1988-Nov-01
Included in the Prior Art Database: 2005-Feb-15
By using strongly helium-diluted silane during the CVD (Chemical Vapor Deposition) of tungsten silicide from tungsten hexafluoride and silane, the efficiency of the chemical reaction, the layer quality and the growth rate are considerably improved. CVD of tungsten silicide from tungsten hexafluoride and silane is generally described by the following reaction: 350Œ C WF6(g) + 2 SiH4(g) ______> WSi2(s) + 6 HF(g) + H2(g). This reaction equation corresponds to a gas flow ratio WF6 : SiH4 of 1 : 2. Standard processes use flow ratio of about 1 160, so that the silane is utilized only about 1.25%. By using strongly diluted silane (1.8% by volume SiH4 in He), tungsten silicide layers were obtained which meet the layer stoichiometry requirement of standard semiconductor processes.