The invention relates to a device for coating substrates in a process chamber (8) of a reactor housing (1), having a gas inlet member (11) for introducing process gases into the process chamber (8), having a gas outlet member (10) for discharging an exhaust gas stream from the process chamber (8) into a particle filter (4), which is disposed in a particle separator housing (3) and has a porous filter medium (16) for out-filtering particles from the exhaust gas stream, which form during a reaction of the process gases. In order to improve the filtering performance of a particle filter at a CVD or PVD device and to specify a suitable particle filter for this intended purpose, the invention suggests that the pore size and the surface quality of the filter medium (16) are selected in such a manner that the particles located in the exhaust gas stream adhere to the surface of the filter medium (16), however do not penetrate the filter medium (16), and the particles grow to conglomerates outside of the filter medium (16), and a mass acceleration device is provided for cleaning the particle filter (4) by mechanically removing the conglomerates.