Chemical-vapor deposition of tungsten is extensively used for very-large-scalae-integrated metallization because of its ability to adequately coat the bottom of high aspect ratio features. Despite this, a detailed model of the surface kinetics is not yet widely accepted. Such a model is essential fur predicting film coverage over deep topography when fluxes and adsorbate coverage can be very different from those on flat surfaces. By considering the dissociative adsorption of H-2 and WF6 and the desorption of H-2 and HF molecules, a new surface kinetic model for tungsten deposition is presented. Time model includes temperature- and coverage-dependent sticking coefficients of adsorbing reactions, the inhibiting effects of F on H-2 adsorption, and multiple reaction pathways. Predictions of the model show reasonable agreement with experimental measurements of H-2 partial pressure dependence of tungsten deposition rate over a wide pressure range. Particularly, the model explains the recently observed effect Of reduced deposition rate when the H-2 pressure becomes comparable to the WF6 pressure. This kinetic model is used by a kinetic thin-film simulator, GROFILMS, to study the W film dt:position over high aspect ratio topography. The him growth profile, the coverage of F and ii, and the impingement fluxes along the film surface are analyzed.