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Ferroelectricity and Antiferroelectricity of Doped Thin HfO 2 ‐Based Films
Author(s) -
Park Min Hyuk,
Lee Young Hwan,
Kim Han Joon,
Kim Yu Jin,
Moon Taehwan,
Kim Keum Do,
Müller Johannes,
Kersch Alfred,
Schroeder Uwe,
Mikolajick Thomas,
Hwang Cheol Seong
Publication year - 2015
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201404531
Subject(s) - materials science , ferroelectricity , thin film , antiferroelectricity , optoelectronics , doping , coercivity , band gap , dopant , capacitor , dielectric , nanotechnology , condensed matter physics , electrical engineering , voltage , physics , engineering
The recent progress in ferroelectricity and antiferroelectricity in HfO 2 ‐based thin films is reported. Most ferroelectric thin film research focuses on perovskite structure materials, such as Pb(Zr,Ti)O 3 , BaTiO 3 , and SrBi 2 Ta 2 O 9 , 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 HfO 2 thin films was first reported. Various dopants, such as Si, Zr, Al, Y, Gd, Sr, and La can induce ferroelectricity or antiferroelectricity in thin HfO 2 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.