Using typical conditions for hot wire chemical vapour deposition (HWCVD) of high quality thin silicon films in a UHV deposition chamber, we studied the silicidation of different filaments mainly varying the filament temperatures between 1700 degrees C and 2130 degrees C. The experiments were done with constant current, running the filament for 5 to 8 h and even longer. The changes of filament resistance and filament temperature with time will be shown and discussed. We investigated the material changes over the whole filament by Scanning Electron microscopy (SEM), especially the thickness of the formed silicide layers. The change of filament resistance depending on the filament temperature was also monitored, pointing out the different behaviour of tungsten and tantalum filaments. As a result, optimum temperature regimes for tantalum and tungsten filaments could be derived with respect to the filament degradation reducing the filament lifetime. Using a specially developed protection for the cold ends, a tungsten filament could be run for more than 139 h under silane with a filament temperature of T(fil)approximate to 2000 degrees C. (C) 2009 Elsevier B.V. All rights reserved.