Apparatus for coating substrates

PCT No. PCT/GB95/00607 Sec. 371 Date Nov. 17, 1995 Sec. 102(e) Date Nov. 17, 1995 PCT Filed Mar. 20, 1995 PCT Pub. No. WO95/25828 PCT Pub. Date Sep. 28, 1995The current invention relates to the provision of apparatus for depositing layers of material onto substrates (2) mounted on a carrier (4) all provided in a vacuum chamber (6) wherein the material is deposited by sputtering of targets of the material from activated magnetrons (7, 7') and the deposited material is reacted by providing a reaction producing means (9) which allows the coating material on the substrates to be conditioned to have the required characteristics. The invention provides that any, or any combination, of the material depositing means and/or reaction producing means are formed from either two magnetrons or a magnetron and counter electrode arrangement which are powered by an alternating voltage power supply which allows a reduction in the occurence of arcing and thereby the dimensions of the apparatus in comparison to conventional apparatus can be substantially reduced.