STABLE AND UNSTABLE CONDITIONS OF THE SPUTTERING MODE BY MODULATING AT LOW-FREQUENCY THE CURRENT OF A MAGNETRON DISCHARGE

It is well known that target poisoning in reactive magnetron sputterin g often causes a time-unstable sputtering mode which can shift toward the reactive mode and a low deposition rate of stoichiometric compound s. This paper presents a description of the relevant time dependent ph enomena, followed by the effect of square-wave modulation of the disch arge current with regard to a titanium target sputtered in Ar-O-2 reac tive mixtures. A high magnitude of the discharge current and low duty are favourable parameters, along with an appropriate frequency compati ble with the pumping speed. This paper also discusses the effect of th e shape of the modulation. (C) 1997 Elsevier Science S.A.