Process for Forming a Tungsten Silicide Layer
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-06
Disclosed is an improved sequence of steps used to fabricate a CVD (chemical vapor deposited) tungsten silicide layer on a surface of a semiconductor structure. 1. The semiconductor structure is cleaned using sulfuric peroxide and diluted hydrofluoric acid. 2. The deposition chamber is flushed with He gas and silane. The chamber is purged at the end of each cleaning to remove all the reaction and byproduct gases. 3. Silane and tungsten hexafluoride are introduced into the chamber where they react to form tungsten silicide. In the beginning of the deposition the ratio of the gases is selected to produce a silicon-rich silicide (i.e., WSix, X > 2.3) at the silicide interface with the semiconductor structure. The remaining portion of the silicide layer will have the constituent elements in their conventional ratio (i.e.