Structural and electrical properties of large area epitaxial VO 2 films grown by electron beam evaporation

Virginie Théry (1) , Alexandre Boulle (1) , Aurelian Crunteanu (2) , Jean-Christophe Orlianges (2) , Arnaud Beaumont (3) , Richard Mayet (4) , Amine Mennai (2) , Françoise Cosset (2) , Annie Bessaudou (2) , Fabert Marc (5)

1 SPCTS-AXE3 - Axe 3 : organisation structurale multiéchelle des matériaux
2 XLIM-RFEI - RF-ELITE : RF-Electronique Imprimée pour les Télécommunications et l'Energie
3 XLIM - XLIM
4 SPCTS - Science des Procédés Céramiques et de Traitements de Surface
5 XLIM-PHOT - Photonique Fibre et Sources Cohérentes

Large area (up to 4 squared inches) epitaxial VO 2 films, with a uniform thickness and exhibiting an abrupt metal-insulator transition with a resistivity ratio as high as 2.85 × 10 4 have been grown on (001)-oriented sapphire substrates by electron beam evaporation. The lattice distortions (mosaicity) and the level of strain in the films have been assessed by X-ray diffraction. It is demonstrated that the films grow in a domain-matching mode where distortions are confined close to the interface which allows to grow high-quality materials despite the high film-substrate lattice mismatch. It is further shown that a post-deposition high-temperature oxygen annealing step is crucial to ensure the correct film stoichiometry and provide the best structural and electrical properties. Alternatively, it is possible to obtain high quality films with an RF discharge during deposition, which hence do not require the additional annealing step. Such films exhibit similar electrical properties and only slightly degraded structural properties.

Domaines: Matériaux; Micro et nanotechnologies/Microélectronique

Virginie Théry, Alexandre Boulle, Aurelian Crunteanu, Jean-Christophe Orlianges, Arnaud Beaumont, et al.. Structural and electrical properties of large area epitaxial VO 2 films grown by electron beam evaporation. Journal of Applied Physics, 2017, 121 (5), pp.055303. ⟨10.1063/1.4975117⟩. ⟨hal-01455047⟩