Epitaxial ferroelectric HfZrO films have been successfully integrated in a capacitor heterostructure on Si(001). The orthorhombic HfZrO phase, [111] out-of-plane oriented, is stabilized in the films. The films present high remnant polarization P close to 20 μC/cm, rivaling with equivalent epitaxial films on single crystalline oxide substrates. Retention time is longer than 10 years for a writing field of around 5 MV/cm, and the capacitors show endurance up to 10 cycles for a writing voltage of around 4 MV/cm. It is found that the formation of the orthorhombic ferroelectric phase depends critically on the bottom electrode, being achieved on LaSrMnO but not on LaNiO. The demonstration of excellent ferroelectric properties in epitaxial films of HfZrO on Si(001) is relevant toward fabrication of devices that require homogeneity in the nanometer scale, as well as for better understanding of the intrinsic properties of this promising ferroelectric oxide.
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http://dx.doi.org/10.1021/acsami.8b18762 | DOI Listing |
Mater Horiz
July 2024
Department of Electronic Engineering, Hanyang University, Seoul 04763, Korea.
We experimentally demonstrate the concept of combination-encoding content-addressable memory (CECAM) that offers much higher content density than any other content-addressable memory devices proposed to date. In this work, CECAM was fabricated and validated with a hafnium-zirconium oxide (HZO) ferroelectric tunnel junction (FTJ) crossbar array. The new CAM structure, which utilizes nonvolatile memory devices, offers numerous advantages including low-current operation (FTJ), standby power reduction (ferroelectric HZO), and increased content density.
View Article and Find Full Text PDFAdv Sci (Weinh)
April 2024
Department of Electrical Engineering and Computer Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, South Korea.
In this study, the development and characterization of 2D ferroelectric field-effect transistor (2D FeFET) devices are presented, utilizing nanoscale ferroelectric HfZrO (HZO) and 2D semiconductors. The fabricated device demonstrated multi-level data storage capabilities. It successfully emulated essential biological characteristics, including excitatory/inhibitory postsynaptic currents (EPSC/IPSC), Pair-Pulse Facilitation (PPF), and Spike-Timing Dependent Plasticity (STDP).
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2024
School of Microelectronics, Xidian University, Xi'an 710071, China.
HfO-ZrO ferroelectric films have recently gained considerable attention from integrated circuit researchers due to their excellent ferroelectric properties over a wide doping range and low deposition temperature. In this work, different HfO-ZrO superlattice (SL) FE films with varying periodicity of HfO (5 cycles)-ZrO (5 cycles) (SL), HfO (10 cycles)-ZrO (10 cycles) (SL), and HfO (15 cycles)-ZrO (15 cycles) (SL) were studied systematically. The HfZrO (HZO) alloy was used as a comparison device.
View Article and Find Full Text PDFAdv Mater
March 2024
Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
Negative capacitance gives rise to subthreshold swing (SS) below the fundamental limit by efficient modulation of surface potential in transistors. While negative-capacitance transition is reported in polycrystalline Pb(ZrTi)O (PZT) and HfZrO (HZO) thin-films in few microseconds timescale, low SS is not persistent over a wide range of drain current when used instead of conventional dielectrics. In this work, the clear nano-second negative transition states in 2D single-crystal CuInPS (CIPS) flakes have been demonstrated by an alternative fast-transient measurement technique.
View Article and Find Full Text PDFNanotechnology
December 2023
Wide Bandgap Semiconductor Technology Disciplines State Key Laboratory, School of Microelectronics, Xidian University, Xi'an, 710071, People's Republic of China.
HfO-based ferroelectric field-effect transistors (FeFETs) are a promising candidate for multilevel memory manipulation and brain-like computing due to the multi-domain properties of the HfOFE films based polycrystalline structure. Although there have been many reports on the working mechanism of the HfO-based FeFET and improving its reliability, the impact of multi-domain effect on the effective carrier mobility () has not been carried out yet. The effectivedetermines the level of readout current and affects the accuracy of the precision of peripheral circuit.
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