Berlin 2024 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 11: Focus Session: (Multi-)Ferroic States II
KFM 11.2: Vortrag
Dienstag, 19. März 2024, 10:00–10:20, EMH 225
In-situ monitoring of polarization dynamics during the epitaxial integration of BaTiO3 thin films on silicon templates — •Bixin Yan, Ipek Efe, Manfred Fiebig, and Morgan Trassin — Department of Materials, ETH Zurich, Switzerland
Ferroelectric oxides host technologically-relevant properties, and their integration onto the CMOS-compatible silicon platform is key for the next generation of oxide electronics. However, the interplay of thermal coefficient mismatch and strain relaxation during the growth of ferroelectric epitaxial thin films on silicon results in a multi-domain configuration in the films, deviating from the application-relevant single-domain state. Here, taking BaTiO3 as our ferroelectric model system, we directly investigate the polarization state of our films during the pulsed laser deposition growth on SrTiO3 (STO)-buffered silicon using in-situ optical second harmonic generation (ISHG). We monitor the emergence of out-of-plane polarization in the early stage of the growth and track in real-time the thickness-dependent in-plane polarized domain formation induced by interfacial strain relaxation. We shed light on the role of growth conditions on the final polarization state of our films and compare the observed behavior with the case of coherently strained thin films grown on conventional single crystalline STO substrates. Finally, ISHG measurements during post-growth cooldown isolate the impact of thermal expansion coefficient mismatch in the final domain architecture in the films. Hence, our work provides new insights into the integration of ferroelectric oxides on silicon templates, a necessary step for the realization of energy-efficient technologies.
Keywords: Ferroelectric oxide; Epitaxial thin film; Pulsed laser deposition; Optical second harmonic generation; Silicon template