[en] Adhesion of non-selective, CVD tungsten to silicon dioxide is a critical issue in the development of tungsten as a metalization for VLSI circuitry. Without special adhesion promoters, tungsten deposited from WF/sub 6/ and H/sub 2/ has typically failed a standard tape test over all types of silicon oxides and nitrides. The reasons for failure of thin films, and CVD tungsten in particular are explored along with standard techniques for improving adhesion of thin films. Experiments are reported which include a number of sputtered metals as adhesion promoters, as well as chemical and plasma treatment of the oxide surface. Sputtered molybdenum is clearly the superior adhesion promoting layer from these tests. Traditional adhesion layers such as chromium or titanium failed as adhesion layers for CVD tungsten possibly due to chemical reactions between the WF/sub 6/ and Cr or Ti

[en] Molybdenum films were deposited from the hydrogen reduction of MoF/sub 6/. The reaction was completely selective against deposition on silicon dioxide. The reaction with silicon is very high rate, and is not self-limiting, in contrast to the analogous reaction between WF/sub 6/ and silicon. Films of selective CVD tungsten, and sputtered TiW and Mo were ineffective as barrier films to the MoF/sub 6/-Si reaction. The TiW and Mo films, when deposited over SiO/sub 2/, were etched clean. MoF/sub 6/ also etched the oxide film. The films deposited over silicon were high in oxygen content and porous