Special Materials Science & Engineering Seminar
Monday, December 9, 2013
210 Mudd, APAM Conference Room
Institut des Nanotechnologies de Lyon, CNRS,
Ecole Centrale de Lyon, 36 avenue Guy de Collongue, 69134 Ecully, France
"Monolithic integration of functional oxides on semiconductors by molecular beam epitaxy"
Abstract: The ability to epitaxially grow the perovskite compound SrTiO3 on Si by molecular beam epitaxy (MBE) opened up the route, 15 years ago, to the monolithic integration of functional oxides on a semiconductor platform. Studies in this field were boosted by the search in the early 2000’s for ultrathin crystalline high permittivity oxides in order to replace the conventional SiO2-based gate oxide in advanced field-effect transistors. MBE provides unique advantages to precisely construct, almost atom by atom, the oxide/semiconductor interface. Interface engineering using Sr- or Ti-based passivation is employed for the epitaxial growth of SrTiO3 templates on Si or GaAs substrates respectively. These templates are subsequently used to grow perovskite complex oxides, which offer a wide range of properties, such as piezoelectricity, pyroelectricity, ferroelectricity, magnetism, multiferroicity or specific electro-optic properties.
In this talk, I will review the challenges associated with the monolithic integration of complex oxides on a semiconductor and more particularly with the integration of ferroelectrics. I will then present a study on BaTiO3 films epitaxially grown on Si(001) by molecular beam epitaxy1. Ferroelectricity – with reversible switching of the polarization - was evidenced by piezoforce microscopy with polarization pointing perpendicular to the silicon substrate. The nano-domain structure will be discussed on the basis of geometrical phase analysis of HR-STEM images. I will conclude with ongoing perspectives on integration in field-effect transistors.
1. C. Dubourdieu et al., Switching of ferroelectric polarization in epitaxial BaTiO3 films on silicon without a conducting bottom electrode, Nature Nanotechnology 8, 748 (2013)
Biography: Catherine Dubourdieu received her Physics Engineer Diploma from ENSPG - Grenoble Polytechnic Institute in 1992 and her PhD degree in Applied Physics from Joseph Fourier University (Grenoble) in 1995. She received the Diplôme d’Habilitation à Diriger des Recherches in 2002 from Grenoble INP.
She spent 18 months as a post-doctoral fellow and Adjunct Assistant Professor at Stevens Institute of Technology in Hoboken (New Jersey). She joined CNRS in 1997, where she is now Directrice de Recherche since 2007.
Her research interests are on the synthesis by CVD and on the properties of oxides heterostructures and nanostructures in relation with their micro/nanostructure. In particular, she investigates size and strain effects on the crystalline, electronic and magnetic properties of functional oxides and work on strain engineering in thin films to finely tune their properties. Her current focus is, on one hand, on ferroelectric and multiferroic materials, and, on the other hand, on high-k dielectrics. She has investigated various aspects of CVD/ALD techniques: precursors benchmarking, process optimization, plasma use for low-temperature deposition. She also works on the integration of functional oxides in micro- and nano-electronics.
She has been teaching (> 1100 hours) at Undergraduate, Graduate and advanced levels at various locations such as Stevens Institute of Technology, Grenoble Institute of Technology, Joseph Fourier University, Collège de l’Ecole Polytechnique (Palaiseau) and the company Altis Semiconductors.
She has supervised or co-supervised 13 PhD students and 11 post-doctoral researchers.
From May 2009 until May 2012, she was invited as a Visiting Scientist at the T.J. Watson Research Center of IBM in Yorktown Heights, where she worked on the integration of ferroelectric oxides on silicon and on the Atomic Layer Deposition of novel oxides.
In June 2012, she joined the Institut des Nanotechnologies de Lyon (INL-CNRS). She currently works on the monolithic integration of functional oxides on semiconductors (Si, III/V, Ge) using molecular beam epitaxy (MBE).
She is currently a member of the Bureau of the GDR CNRS 'Matériaux Multiferroïques' and a member of the ITRS (International Technology Roadmap for Semiconductors) working in the Emerging Research Materials group.
Award: Bronze medal CNRS 2001
Host: I.C. Noyan