Abstract: Method and an apparatus for coating a substrate from electrically conductive targets (3, 4) in a reactive atmosphere, comprising a power source (12, 13, 14) which is connected to cathodes (1, 2) disposed in an evacuable coating chamber (15) and cooperating electrically with the targets (3, 4), two anodes (5, 6) electrically separated from one another and from the sputtering chamber (15) being provided, which lie in a plane between the cathodes (1, 2) and the substrate (7), the two output terminals (12a, 12b) of the secondary winding of a transformer (12) connected, with interposition of a choke coil (14), to a medium frequency generator (13) being connected each to a cathode (1 and 2, respectively) via two supply lines (20, 21) and the two supply lines (20, 21) being connected via a branch line (22) into which a resonant circuit is inserted, and each of the two supply lines (20, 21) being coupled both via a first network (16 and 17, respectively) to the coating chamber and via a corresponding second network (

Abstract: In a sputtering cathode arrangement according to the magnetron principle for the coating of a flat circular substrate, with a circular ring-shaped target and an outer mask and inner mask disposed between the target and the substrate, a magnet system with a yoke plate being disposed in back of the target for the production of the magnetron effect, the inner mask is fastened to a mask holder which is brought through the center of the target, the magnet system with the yoke plate (8) being disposed for rotation about an axis of rotation (M) going through the center of the target, and consisting of at least two magnet arrangements (9,9', . . . ; 10,10', . . .