[en] The growth of copper crystals on copper, by thermal decomposition of CuF₂, has been studied previously. It has been observed that, at a given temperature, the deposition rate reaches a maximum value which seems to be controlled only by the desorption of fluorine from a complete monolayer.Recent results concerning the thermal decomposition of TiF₄ and Ti and FeF₂ on Fe confirm this mechanism and give a measure of the heat of desorption of fluorine. The deposition rate can be generally improved if one uses the thermal decomposition of subfluorides. A method was developed based on sub-fluoride preparation in situ near the substrate. According to this new method, the formation of the sub-fluoride and its thermal decomposition occur simultaneously. This process is very suitable for the deposition of refractory metals at relatively low temperatures. Some examples are given, concerning mainly the decomposition of WF₅. Generally, in comparison with other halides, it seems that the thermal decomposition of fluorides is preferable for obtaining very high quality deposits, provided the technology necessary for fluorine chemistry is available