Abstract: Apparatus and process for vapor depositing epitaxial films on substrates. A gaseous reactant is introduced into a reaction chamber formed from a material, such as quartz, which is transparent and non-obstructive to radiant heat energy transmitted at a predetermined short wave length. A graphite susceptor, which is opaque to and absorbs the radiant heat energy, is positioned within the reaction chamber and supports the substrates to be coated. The susceptor is heated while the walls of the reaction chamber remain cool to preclude deposition of epitaxial film on the walls. To insure uniform heating of the susceptor, the same may be moved relative to the radiant heat source which, in the preferred embodiment, comprises a bank of tungsten filament quartz-iodine high intensity lamps which transmit radiant heat energy against the susceptor as a non-focused generally uniform energy field.