A compact vapor source of conductive target material sputtered by 3-keV ions at 0.05-Pa pressure

Abstract

A vapor source is developed its 80-mm-diameter and 15-mm-thick flat target being positioned on the bottom of a 120-mm-diameter and 70-mm-deep hollow cathode, isolated from the cathode and sputtered by 1–4-keV argon ions. A permanent magnet induces an axially symmetric heterogeneous magnetic field, the field induction on the target surface reaching 20 mT and the field lines of force being diverging from the target surface and crossing the cathode surface. The cathode bombardment by 1–3-keV secondary electrons emitted by the target results in an increase of the electron emission current in the cathode circuit and enables to reduce the argon pressure down to 0.05 Pa. It allows a collisionless transport of the sputtered metal atoms to a substrate thus keeping their initial energy amounting to tens of electronvolts. A higher energy of deposited atoms improves quality of coatings, for instance of Ti3SiB2 films, their deposition rate on a substrate distanced at 0.1–0.2 m from the target amounting to 10–20 µm/h at 1-A current in the target circuit and 3-keV energy of sputtering ions. This value is one order of magnitude higher in comparison with the target sputtering in a planar magnetron discharge by 300–500-eV argon ions at the same 1-A current in the target circuit.