Synthesis of iron oxide films by reactive magnetron sputtering assisted by plasma emission monitoring

E. Aubry (1) , T. Liu (2) , A. Dekens (2) , Frédéric Perry (3) , S. Mangin (2) , Thomas Hauet (2) , Alain Billard (4)

1 Nipson Technology
2 IJL - Institut Jean Lamour
3 PVDco Sarl
4 FEMTO-ST - Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174)

• FeO films were synthesized by pulsed-DC magnetron sputtering from metallic target. • The film oxidation was controlled with a plasma emission monitoring system. • Special attention was paid to the sample position relative to the target axis. • Structural features depend on the oxidation rate of the growing films. • FeO behaviors are tuned from hematite semiconductor to magnetite semimetal properties. A R T I C L E I N F O Keywords: FeO Reactive sputtering Plasma emission monitoring Hematite Magnetite A B S T R A C T Iron oxide films were synthesized by pulsed-DC magnetron sputtering from a metallic target in Ar and O 2 gas mixtures. Plasma emission monitoring was implemented to accurately control the metal-to-oxygen ratio in the coating through the chemical state of the iron target. The intensity of the Fe* emission line was maintained at a given value (setpoint) by regulating the introduced oxygen flow rate. In addition, the oxidation rate of the growing film was adjusted by controlling the oxidation-to-deposition rate ratio as a function of the position of the substrates relative to the magnetron axis. The iron oxide films were characterized by X-ray diffraction, UV-VIS spectrophotometry, electrical measurement and vibrating sample magnetometry. In addition to the crys-tallization of pure hematite and magnetite phases, both phases coexist in a transition domain for a short range of setpoint depending on the oxidation-to-deposition rate ratio. The electrical, optical and magnetic behaviors of the FeO x films suggest that the relative proportion of phases can be tailored in this range. The FeO x film behaviors can then be tuned from the hematite semiconductor properties to the semi-metallic magnetite properties .

Domaines: Science des matériaux [cond-mat.mtrl-sci]

E. Aubry, T. Liu, A. Dekens, Frédéric Perry, S. Mangin, et al.. Synthesis of iron oxide films by reactive magnetron sputtering assisted by plasma emission monitoring. Materials Chemistry and Physics, 2019, 223, pp.360-365. ⟨10.1016/j.matchemphys.2018.11.010⟩. ⟨hal-01950283⟩