Structural study and ferroelectricity of epitaxial BaTiO3 films on silicon grown by molecular beam epitaxy

Lucie Mazet (1) , Romain Bachelet (1) , Lamis Louahadj (1) , David Albertini (2) , Brice Gautier (3) , Robin Cours (4) , Sylvie Schamm-Chardon (4, 5) , Guillaume Saint-Girons (1) , Catherine Dubourdieu (6)

1 INL - H&N - INL - Hétéroepitaxie et Nanostructures
2 LPM - Laboratoire de physique de la matière
3 INL - DE - INL - Dispositifs Electroniques
4 CEMES - Centre d'élaboration de matériaux et d'études structurales
5 CEMES-MEM - Matériaux et dispositifs pour l'Electronique et le Magnétisme
6 INL - Institut des Nanotechnologies de Lyon

Integration of epitaxial complex ferroelectric oxides such as BaTiO3 on semiconductor substrates depends on the ability to finely control their structure and properties, which are strongly correlated. The epitaxial growth of thin BaTiO3 films with high interfacial quality still remains scarcely investigated on semiconductors; a systematic investigation of processing conditions is missing although they determine the cationic composition, the oxygen content, and the microstructure, which, in turn, play a major role on the ferroelectric properties. We report here the study of various relevant deposition parameters in molecular beam epitaxy for the growth of epitaxial tetragonal BaTiO3 thin films on silicon substrates. The films were grown using a 4 nm-thick epitaxial SrTiO3 buffer layer. We show that the tetragonality of the BaTiO3 films, the crystalline domain orientations, and SiO2 interfacial layer regrowth strongly depend on the oxygen partial pressure and temperature during the growth and on the post-deposition anneal. The ferroelectricity of the films, probed using piezoresponse force microscopy, is obtained in controlled temperature and oxygen pressure conditions with a polarization perpendicular to the surface.

Domaines: Micro et nanotechnologies/Microélectronique; Science des matériaux [cond-mat.mtrl-sci]

Lucie Mazet, Romain Bachelet, Lamis Louahadj, David Albertini, Brice Gautier, et al.. Structural study and ferroelectricity of epitaxial BaTiO3 films on silicon grown by molecular beam epitaxy. Journal of Applied Physics, 2014, 116 (21), pp.214102. ⟨10.1063/1.4902165⟩. ⟨hal-01489886⟩