Chemically Vapor Deposited Tungsten Silicide Films Using Dichlorosilane in a Single–Wafer Reactor

S. G. Telford, M. Chang, A. K. Sinha, M. Eizenberg, T. R. Gow

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24 Scopus citations


Compositionally uniform (in depth and in lateral position) chemically vapor deposited WSix films were deposited on 200 mm Si wafers in a single–wafer reactor using SiH2Cl2/WF6 chemistry. A process window was found to produce highly uniform compositions in the range of 2.2 ⩽x ⩽2.6, regardless of the nucleation surface, SiO2 or poly–Si. 900°C annealing in Nz of such films deposited on P–doped poly–Si resulted in a uniform reduction of x to a value of 2.1 to 2.2. In contrast, as deposited dichlorosilane–WSix films which are Si-poor at the interface, were found to develop a high concentration of Si in the middle layer of the annealed structure. The as–deposited resistivity was found to increase linearly with x with a value of ~750 µΩ. cm for x =2.5. Upon annealing, the resistivities decreased to values in the range of 80 to 110 µΩ. cm. The as–deposited films were predominantly in the hexagonal structure of WSi2, which transformed to the tetragonal structure upon annealing at temperatures higher than 600°C. As-deposited stresses were in the range of (1.3 to 1.6) - 1010 dyne/cm2, and upon annealing reduced to ~ 1.1010 dyne/cm2. The films had a very good step coverage even at high aspect ratios and did not crack or peel off upon annealing. The films contained relatively low levels of impurities: F ~ 6 1016 to 2 •1017 and Cl ~ 5 • 1017 to 1 1019 atom/cm3. This systematic study reviews the correlations between the structural, compositional, mechanical, and electrical properties of the as-deposited and the annealed silicide films.

Original languageEnglish
Pages (from-to)3689-3701
Number of pages13
JournalJournal of the Electrochemical Society
Issue number12
StatePublished - Dec 1993
Externally publishedYes


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