We have succeeded in the rapid epitaxial growth of Si, Ge, and SiGe films on Si substrates below 670°C by reactive CVD utilizing the spontaneous exothermic reaction between SiH4, GeH4, and F2. Mono-crystalline SiGe epitaxial films with Ge composition ranging from 0.1 to 1.0 have been successfully grown by reactive CVD for the first time. This technique has also been successfully applied to the growth of these films on silicon-on-glass substrates by a 20-50°C increase of the heating temperature. Over 10 μm thick epitaxial films at 3 nm/s growth rate are obtained. The etch pit density of the 5.2 μm-thick Si0.5Ge 0.5 film is as low as 5 × 106 cm-2 on top. Mobilities of the undoped SiGe and Si films are 180 to 550 cm 2/Vs, confirming the good crystallinity of the epitaxial films.