The kinetics of the hydrogen reduction of tungsten hexafluoride were studied. The growth rate was measured as a function of the process conditions, which were determined in situ by means of laser Raman scattering. The partial pressures were measured at a height of 17 mm above the center of a 100 mm wafer in a cold-wall single-wafer low-pressure chemical vapor deposition reactor The hydrogen reduction reaction was on the order of 1/6 in WF6 and 1/2 in H-2. The activation energy was equal to 64 kJ mol(-1). An analysis of available reaction paths revealed that either the formation or the desorption of HF is the rate-limiting step. Since only one activation energy is present, the rate-limiting step is valid for the complete regime that was investigated.