Ronny Kleinhempel

High-rate deposition of MgO by reactive ac pulsed magnetron sputtering in the transition mode

A reactive ac pulsed dual magnetron sputtering process for MgO thin-film deposition was equipped with a closed-loop control of the oxygen flow rate (FO2) using the 285nm magnesium radiation as input. Owing to this control, most of the unstable part of the partial pressure versus flowrate curve became accessible. The process worked steadily and reproducible without arcing. A dynamic deposition rate of up to 35nmm∕min could be achieved, which was higher than in the oxide mode by about a factor of 18. Both process characteristics and film properties were investigated in this work in dependence on the oxygen flow, i.e., in dependence on the particular point within the transition region where the process is operated. The films had very low extinction coefficients (<5×10−5) and refractive indices close to the bulk value. They were nearly stoichiometric with a slight oxygen surplus (Mg∕O=48∕52) which was independent of the oxygen flow. X-ray diffraction revealed a prevailing (111) orientation. Provided that appr...