Journal ArticleDOI
Ferroelectricity in Simple Binary ZrO2 and HfO2
Johannes Müller,T. S. Böscke,Uwe Schröder,Stefan Mueller,D. Bräuhaus,Ulrich Böttger,Lothar Frey,Thomas Mikolajick +7 more
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TLDR
A structural investigation revealed the orthorhombic phase to be of space group Pbc2(1), whose noncentrosymmetric nature is deemed responsible for the spontaneous polarization in this novel, nanoscale ferroelectrics.Abstract:
The transition metal oxides ZrO2 and HfO2 as well as their solid solution are widely researched and, like most binary oxides, are expected to exhibit centrosymmetric crystal structure and therewith linear dielectric characteristics. For this reason, those oxides, even though successfully introduced into microelectronics, were never considered to be more than simple dielectrics possessing limited functionality. Here we report the discovery of a field-driven ferroelectric phase transition in pure, sub 10 nm ZrO2 thin films and a composition- and temperature-dependent transition to a stable ferroelectric phase in the HfO2–ZrO2 mixed oxide. These unusual findings are attributed to a size-driven tetragonal to orthorhombic phase transition that in thin films, similar to the anticipated tetragonal to monoclinic transition, is lowered to room temperature. A structural investigation revealed the orthorhombic phase to be of space group Pbc21, whose noncentrosymmetric nature is deemed responsible for the spontaneous...read more
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Journal ArticleDOI
Ferroelectricity and Antiferroelectricity of Doped Thin HfO2‐Based Films
Min Hyuk Park,Young Hwan Lee,Han Joon Kim,Yu Jin Kim,Taehwan Moon,Keum Do Kim,Johannes Müller,Alfred Kersch,Uwe Schroeder,Thomas Mikolajick,Cheol Seong Hwang +10 more
TL;DR: 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.
Journal ArticleDOI
Physical Mechanisms behind the Field-Cycling Behavior of HfO2-Based Ferroelectric Capacitors
Milan Pešić,Franz P. G. Fengler,Luca Larcher,Andrea Padovani,Tony Schenk,Everett D. Grimley,Xiahan Sang,James M. LeBeau,Stefan Slesazeck,Uwe Schroeder,Thomas Mikolajick +10 more
TL;DR: In this paper, the authors identify the root cause for the increase of the remnant polarization during the wake-up phase and subsequent polarization degradation with further cycling of a hafnium oxide-based ferroelectric random access memory (FeRAM).
Journal ArticleDOI
Thin-film ferroelectric materials and their applications
TL;DR: In this article, the authors focus on thin-film ferroelectric materials and, in particular, on the possibility of controlling their properties through the application of strain engineering in conventional and unconventional ways, and discuss several exciting possibilities for the development of new devices, including those in electronic, thermal, photovoltaic applications, and transduction sensors and actuators.
Journal ArticleDOI
The origin of ferroelectricity in Hf1−xZrxO2: A computational investigation and a surface energy model
TL;DR: In this paper, the structural, thermal, and dielectric properties of the ferroelectric phase of HfO2, ZrO2 and Hf0.5O2 are investigated with carefully validated density functional computations.
Journal ArticleDOI
Evolution of phases and ferroelectric properties of thin Hf0.5Zr0.5O2 films according to the thickness and annealing temperature
TL;DR: In this paper, the effects of annealing temperature (Tanneal) and film thickness (tf) on the crystal structure and ferroelectric properties of Hf 0.5Zr0.5O2 films were examined.
References
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Journal ArticleDOI
Ferroelectricity in hafnium oxide thin films
TL;DR: In this paper, it was shown that crystalline phases with ferroelectric behavior can be formed in thin thin films of SiO2 doped hafnium oxide, which is suitable for field effect transistors and capacitors due to its excellent compatibility to silicon technology.
Journal ArticleDOI
First-principles study of structural, vibrational, and lattice dielectric properties of hafnium oxide
Xinyuan Zhao,David Vanderbilt +1 more
TL;DR: In this paper, the dielectric susceptibility tensors for the three low-pressure phases of the zone-center phonon modes were investigated with both local density approximation (LDA) and generalized gradient approximation (GDA).
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Incipient Ferroelectricity in Al-Doped HfO2 Thin Films
Stefan Mueller,Johannes Mueller,Aarti Singh,Stefan Riedel,Jonas Sundqvist,Uwe Schroeder,Thomas Mikolajick +6 more
TL;DR: In this paper, a structural investigation of the electrically characterized capacitors by grazing incidence X-ray diffraction is presented in order to gain further insight on the potential origin of ferroelectricity.
Journal ArticleDOI
Ferroelectricity in yttrium-doped hafnium oxide
Johannes Müller,Uwe Schröder,T. S. Böscke,I. Müller,Ulrich Böttger,L. Wilde,Jonas Sundqvist,Martin Lemberger,P. Kücher,Thomas Mikolajick,Lothar Frey +10 more
TL;DR: In this article, structural and electrical evidence for a ferroelectric phase in yttrium doped hafnium oxide thin films is presented, based on X-ray diffraction.
Journal ArticleDOI
Development of hafnium based high-k materials—A review
TL;DR: In this paper, the authors review how metal oxide-based gate dielectrics emerged from all likely candidates to become the new gold standard in the microelectronics industry, its different phases, reported electrical properties, and materials processing techniques, including carrier scattering, interface state passivation, phonon engineering, and nano-scale patterning.