title: Ferroelectricity and antiferroelectricity of doped thin HfO2-based films.
abstract: The recent progress in ferroelectricity and antiferroelectricity in HfO2-based thin films is reported. Most ferroelectric thin film research focuses on perovskite structure materials, such as Pb(Zr,Ti)O3, BaTiO3, and SrBi2Ta2O9, which are considered to be feasible candidate materials for non-volatile semiconductor memory devices. However, these conventional ferroelectrics suffer from various problems including poor Si-compatibility, environmental issues related to Pb, large physical thickness, low resistance to hydrogen, and small bandgap. In 2011, ferroelectricity in Si-doped HfO2 thin films was first reported. Various dopants, such as Si, Zr, Al, Y, Gd, Sr, and La can induce ferro-electricity or antiferroelectricity in thin HfO2 films. They have large remanent polarization of up to 45 μC cm(-2), and their coercive field (≈1-2 MV cm(-1)) is larger than conventional ferroelectric films by approximately one order of magnitude. Furthermore, they can be extremely thin (<10 nm) and have a large bandgap (>5 eV). These differences are believed to overcome the barriers of conventional ferroelectrics in memory applications, including ferroelectric field-effect-transistors and three-dimensional capacitors. Moreover, the coupling of electric and thermal properties of the antiferroelectric thin films is expected to be useful for various applications, including energy harvesting/storage, solid-state-cooling, and infrared sensors.
authors: Department of Materials Science and Engineering, Seoul National University, Seoul, 151-744, Republic of Korea; Inter-university Semiconductor Research Center, College of EngineeringSeoul National University, Seoul, 151-744, Republic of Korea.
authors: Min Hyuk
authors: MH
authors: Park
authors: Young Hwan
authors: YH
authors: Lee
authors: Han Joon
authors: HJ
authors: Kim
authors: Yu Jin
authors: YJ
authors: Kim
authors: Taehwan
authors: T
authors: Moon
authors: Keum Do
authors: KD
authors: Kim
authors: Johannes
authors: J
authors: Müller
authors: Alfred
authors: A
authors: Kersch
authors: Uwe
authors: U
authors: Schroeder
authors: Thomas
authors: T
authors: Mikolajick
authors: Cheol Seong
authors: CS
authors: Hwang
keywords: antiferroelectricity; doped hafnium oxide; electrocalroric effects; ferroelectricity; nonvolatile memory; pyroelectricity