Fe and Ti cathodes sputtering by oxygen plasma in DC glow discharges

Sputtering yields of iron and titanium cathodes have been measured over wide ranges: (0.1 < p < 0.373 mbar) and (0.25 < jd < 1 mA/cm2) of oxygen pressure (p) and current density (jd) of the O2/Fe discharge. The effective sputtering yields Yefs run from 0.0017 up to 0.136 [AFe/AO]. These yields are very low if compared with those characteristic of other discharge sets. The Monte-Carlo modelling of the oxygen plasma-metallic cathode interface allows the explanation of the effect of plasma characteristics on these yields and a stoichiometry of the cathode subsurface layer. High oxidation of subsurface cathode layer, redeposition of sputtered atoms and non-volatile character of metal oxides are main reasons for low values of effective sputtering yields as well as their dependence on working gas pressure.