PROCESS AND CIRCUIT FOR THE BIPOLAR PULSED SUPPLY OF POWER IN LOW-PRESSURE PLASMAS

摘要

The greatest possible power is to be supplied to the low-pressure discharge at the median point of a period of time. The same power is to be supplied to each pole although the impedance differs widely. In a plasma and surface treatment technology plant with at least two electrodes and a power supply, the outputs of at least two potential-free d.c. power supplies are connected in such a way that an output of one of them is conductively connected to that of the other having the same polarity. Via a switch connected to the electrodes by each line, the other outputs of which are connected together to the other outputs of the d.c. source, said switches are actuated at the rate of the pole change frequency by a clock unit. The switches are opened on the occurence of an arc discharge. The process is used in bipolar pulsed sputtering for depositing electrically insulating coatings on workpieces. Such coatings are preferably used for mechanical protection, wear prevention and the improvement of sliding properties.