摘要 |
An apparatus for the reactive coating of a substrate 1 with an electrically insulative material, for example silicon dioxide SiO2, comprises a power supply source 10 connected to a cathode 5 which is disposed in an evacuable coating chamber 15, 15a and surrounds the magnets 7, 8, 9. This cathode electrically interacts with the target 3 which is sputtered and the sputtered particles thereof are deposited on the substrate 1. A process gas and a reactive gas, e.g. argon with oxygen, are introduced into the coating chamber 15, 15a. The apparatus comprises two electrodes 44, 5 which are electrically insulated from one another and from the sputtering chamber 26, wherein the one electrode is a magnetron cathode 5 where the cathode base 11 and the material of the target 3 are electrically connected to each other and the other electrode functions as an anode 44 in the plasma discharge. The DC power supply source 10 has an electrically floating output and the negative pole thereof is connected to cathode 5 and the positive pole thereof to anode 44. In order to achieve a stable coating process, a first low-induction, HF-suitable capacitor 34 is inserted between cathode 5 and anode 44 and a second low-induction, HF-suitable capacitor 35 between anode 44 and the electrically insulated vacuum chamber 25.
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