Square-wave low-frequency modulation of the discharge current for high rate deposition of stoichiometric ceramic films

Low-frequency modulation of the discharge current is as a convenient way of overcoming the drawbacks associated with unstable behaviour, i.e. the hysteresis effect, often encountered in reactive magnetron sputtering. In this paper, we present the main trends of a square-wave low-frequency modulation of the discharge current. Particular attention is paid to the description of the characteristic times of poisoning and cleaning of the target surface, at the origin of the process stabilisation close to the elemental or reactive sputtering mode. Finally, we focus on the characteristic time at the surface of the substrate, where it is shown that the high-rate deposition of stoichiometric titanium dioxide is obtained by depositing a sub-stoichiometric layer at the end of the step high of the modulation, which reoxidises during the following step low.