Ferroelectric HfO2: Epitaxial films as a model system for fundamental understanding and property improvement
Contents
Host
Professor Dr. Jie Wang
Professor Dr. Jie Wang is a Qiushi Distinguished Professor at Zhejiang University. He received his Ph.D. from the Hong Kong University of Science and Technology (HKUST) in 2006. He subsequently conducted postdoctoral research at HKUST (2006–2007) and as a Humboldt Research Fellow at the Karlsruhe Institute of Technology, Germany (2007–2009). He joined Zhejiang University in 2009 and was promoted to Full Professor in 2015. His research focuses on first-principles calculations and phase-field modeling of ferroelectric, ferromagnetic, and multiferroic materials. He has led over 10 national and provincial funded projects and published more than 200 SCI papers in prestigious journals including Nature Communications, PNAS, and Physical Review Letters. He received the Xu Zhilun Mechanics Outstanding Teacher Award in 2015 and has been listed among the World’s Top 2% Scientists since 2024. He serves on the editorial boards of Microstructures, Scientific Reports, and Materials, and has delivered numerous invited talks and chaired international symposia such as the 5th International Symposium on Phase-Field Modelling in Materials Science (PF24).
Speaker
Professor Florencio Sánchez
Institute of Materials Science of Barcelona (ICMAB), Spanish National Research Council (CSIC), Spain
Prof. Florencio Sánchez is a Research Professor at the Institute of Materials Science of Barcelona (ICMAB), a research center of the Spanish National Research Council (CSIC) focused on research in functional materials. He is an internationally recognized expert in functional oxide thin films and complex oxide heterostructures, with a particular focus on ferroelectric and multiferroic materials.
His research centers on the epitaxial growth, interface engineering, and property control of advanced oxide systems, including emerging ferroelectric hafnium oxide (HfO2) for CMOS-compatible memory and energy applications. He leads the FOXEM group, which is known for contributions to strain, defects and interface engineering, epitaxial integration of oxides on silicon, and oxide-based electronic devices.
Prof. Sánchez has published extensively in leading materials science journals and is widely recognized for advancing both the fundamental understanding and device integration of functional oxide materials for next-generation electronic technologies.
His research centers on the epitaxial growth, interface engineering, and property control of advanced oxide systems, including emerging ferroelectric hafnium oxide (HfO2) for CMOS-compatible memory and energy applications. He leads the FOXEM group, which is known for contributions to strain, defects and interface engineering, epitaxial integration of oxides on silicon, and oxide-based electronic devices.
Prof. Sánchez has published extensively in leading materials science journals and is widely recognized for advancing both the fundamental understanding and device integration of functional oxide materials for next-generation electronic technologies.
Abstract
The discovery that a metastable phase in HfO2 possesses robust ferroelectric properties at room temperature and can be stabilized in nanometric doped HfO2 films under CMOS-compatible conditions has generated enormous interest in academia and the semiconductor industry. Progress has been remarkable, and the first memory devices are ready for market. However, faster progress is hampered by the material's complexity, with the common coexistence of polymorphs and multiple defects critically affecting ferroelectric polarization and reliability. Epitaxial films, with their more controlled microstructure, have emerged as a complement to CMOS-compatible polycrystalline HfO2, serving as a model system and facilitating the understanding of its properties.
In this seminar, we will describe the challenges of epitaxial growth of the metastable phase of HfO2 and outline the unconventional epitaxy mechanism that enables its stabilization on perovskite substrates. The use of these substrates allows for tuning the polymorphs formed, which has been used to maximize polarization and elucidate the endurance-polarization dilemma of ferroelectric HfO2. Epitaxial films are also ideal systems for analyzing the relevance of strain effects on ferroelectric hafnia, as well as for experimentally determining the intrinsic polarization of this ferroelectric oxide. Finally, I will mention some of our other recent achievements on epitaxial HfO2, such as determining effects of dopants, controlling oxygen vacancies and other defects in films grown by pulsed laser deposition, and developing devices for storage of energy, polarization control by light or magnetoelectric effects.
Keywords: Ferroelectrics, HfO2, Thin films, Epitaxy, Functional oxides
In this seminar, we will describe the challenges of epitaxial growth of the metastable phase of HfO2 and outline the unconventional epitaxy mechanism that enables its stabilization on perovskite substrates. The use of these substrates allows for tuning the polymorphs formed, which has been used to maximize polarization and elucidate the endurance-polarization dilemma of ferroelectric HfO2. Epitaxial films are also ideal systems for analyzing the relevance of strain effects on ferroelectric hafnia, as well as for experimentally determining the intrinsic polarization of this ferroelectric oxide. Finally, I will mention some of our other recent achievements on epitaxial HfO2, such as determining effects of dopants, controlling oxygen vacancies and other defects in films grown by pulsed laser deposition, and developing devices for storage of energy, polarization control by light or magnetoelectric effects.
Keywords: Ferroelectrics, HfO2, Thin films, Epitaxy, Functional oxides
