Apparatus for applying thin layers to a substrate

The invention relates to an apparatus for applying thin layers to a substrate, by sputtering a cathode mounted target in a vacuum chamber. A process gas source () is connected to the vacuum chamber (), and a metering valve () actuated by an automatic controller is installed between the vacuum chamber () and the process gas source (). A potentiometric measurement electrode compares the amount of a gas in the vacuum chamber () with a reference gas by way of a reference electrode or with a solid body substituting for the reference electrode and sends a signal to automatic control unit (), which contains a signal amplifier. The control unit then drives the generator of the power supply or the metering valve for the process gas.