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 sputtering often causes a time-unstable sputtering mode which can shift toward the reactive mode and a low deposition rate of stoichiometric compounds. This paper presents a description of the relevant time dependent phenomena, followed by the effect of square-wave modulation of the discharge current with regard to a titanium target sputtered in Ar-O-2 reactive mixtures. A high magnitude of the discharge current and low duty are favourable parameters, along with an appropriate frequency compatible with the pumping speed. This paper also discusses the effect of the shape of the modulation. (C) 1997 Elsevier Science S.A.