| AVS 61st International Symposium & Exhibition | |
| Electronic Materials and Processing | Monday Sessions |
| Session EM+MI+NS-MoM |
| Session: | Complex Oxides and Their Interfaces |
| Presenter: | Catherine Dubourdieu, Institut des Nanotechnologies de Lyon (INL) - CNRS - ECL, France |
| Authors: | L. Mazet, Institut des Nanotechnologies de Lyon (INL) - CNRS - ECL, France R. Bachelet, Institut des Nanotechnologies de Lyon (INL) - CNRS - ECL, France G. Saint-Girons, Institut des Nanotechnologies de Lyon (INL) - CNRS - ECL, France D. Albertini, Institut des Nanotechnologies de Lyon (INL) - CNRS - INSA de Lyon, France B. Gautier, Institut des Nanotechnologies de Lyon (INL) - CNRS - INSA de Lyon, France M.M. Frank, IBM T.J. Watson Research Center J. Jordan-Sweet, IBM T.J. Watson Research Center I. Lauer, IBM T.J. Watson Research Center V. Narayanan, IBM T.J. Watson Research Center M. Hytch, CEMES - CNRS - Université de Toulouse, France S. Schamm-Chardon, CEMES - CNRS - Université de Toulouse, France C. Dubourdieu, Institut des Nanotechnologies de Lyon (INL) - CNRS - ECL, France |
| Correspondent: | Click to Email |
Ferroelectric oxides integrated on a semiconductor substrate are of particular interest for various applications such as memory or logic devices, electro-optic devices or as piezoelectric materials for sensors and actuators. Among the ferroelectric compounds, BaTiO3 is an attractive candidate for large-scale applications compared to Pb- or Bi-based oxides. It is a well-known perovskite largely studied for its dielectric, piezoelectric and ferroelectric properties.
In this talk, I will briefly review the challenges associated with the monolithic integration of crystalline complex oxides on a semiconductor and more particularly with the integration of ferroelectrics. Molecular Beam Epitaxy (MBE) provides unique advantages to precisely construct, almost atom by atom, the oxide/semiconductor interface.
I will then present an experimental work on the epitaxy of BaTiO3 thin films (1.2 - 20 nm) on silicon and Si1-xGex substrates. Films are grown by MBE, in the thickness range of 1.2-20 nm. Different growth conditions such as temperature and oxygen pressure are explored to optimize the BaTiO3 film quality and to minimize the SiO2 interfacial layer regrowth between Si and the SrTiO3 buffer layer. The surface quality is monitored in-situ by reflection high-energy electron diffraction (RHEED) and ex-situ by X-ray reflectometry (XRR) and atomic force microscopy (AFM). The crystalline structure is studied by conventional and synchrotron X-ray diffraction. It is also investigated at the nanoscale using advanced transmission electron microscopy techniques. Strain maps determined with high precision (0.05%), 5 nm spatial resolution and with a large field of view (1 μm) using dark field electron holography will be discussed for selected samples. The crystalline domain orientations (c- versus a-domains) will be discussed with respect to the growth conditions and thickness. The ferroelectric properties are investigated by piezoresponse force microscopy (PFM). Ferroelectric films are obtained in optimized conditions that will be discussed. Ultrathin films of few monolayers are investigated to determine the onset of ferroelectricity.
I will conclude with ongoing perspectives on the integration of such heterostructures in new field-effect devices for low power logic applications.