Hafnium-based ferroelectric films,remaining their ferroelectricity down to nanoscale thickness,present a promising application for low-power logic devices and nonvolatile memories.It has been appealing for researchers...Hafnium-based ferroelectric films,remaining their ferroelectricity down to nanoscale thickness,present a promising application for low-power logic devices and nonvolatile memories.It has been appealing for researchers to reduce the required temperature to obtain the ferroelectric phase in hafnium-based ferroelectric films for applications such as flexible and wearable electronics.This work demonstrates that a remanent polarization(P_(r))value of>5μC/cm^(2)can be obtained in asdeposited Hf_(0.5)Zr_(0.5)O_(2)(HZO)films that are fabricated by thermal atomic layer deposition(TALD)under low temperature of 250℃.The ferroelectric orthorhombic phase(o-phase)in the as-deposited HZO films is detected by scanning transmission electron microscopy(STEM).This low fabrication temperature further extends the compatibility of ferroelectric HZO films to flexible electronics and avoids the cost imposed by following high-temperature annealing treatments.展开更多
In recent years,the emergence of numerous applications of artificial intelligence(AI)has sparked a new technological revolution.These applications include facial recognition,autonomous driving,intelligent robotics,and...In recent years,the emergence of numerous applications of artificial intelligence(AI)has sparked a new technological revolution.These applications include facial recognition,autonomous driving,intelligent robotics,and image restoration.However,the data processing and storage procedures in the conventional von Neumann architecture are discrete,which leads to the“memory wall”problem.As a result,such architecture is incompatible with AI requirements for efficient and sustainable processing.Exploring new computing architectures and material bases is therefore imperative.Inspired by neurobiological systems,in-memory and in-sensor computing techniques provide a new means of overcoming the limitations inherent in the von Neumann architecture.The basis of neural morphological computation is a crossbar array of high-density,high-efficiency non-volatile memory devices.Among the numerous candidate memory devices,ferroelectric memory devices with non-volatile polarization states,low power consumption and strong endurance are expected to be ideal candidates for neuromorphic computing.Further research on the complementary metal-oxide-semiconductor(CMOS)compatibility for these devices is underway and has yielded favorable results.Herein,we first introduce the development of ferroelectric materials as well as their mechanisms of polarization reversal and detail the applications of ferroelectric synaptic devices in artificial neural networks.Subsequently,we introduce the latest developments in ferroelectrics-based in-memory and in-sensor computing.Finally,we review recent works on hafnium-based ferroelectric memory devices with CMOS process compatibility and give a perspective for future developments.展开更多
Over the past two decades,flexible electronics have attracted numerous attentions for their potential use as flexible,stretchable,portable and conformable devices in various fields including computing,energy harvestin...Over the past two decades,flexible electronics have attracted numerous attentions for their potential use as flexible,stretchable,portable and conformable devices in various fields including computing,energy harvesting,robotics,sensors and transductors or health monitoring.展开更多
Heterovalent doped(K_(0.48-0.07)xNa_(0.52-0.43)xBi_(0.5)x)(Nb_(0.95-0.95x)Sb_(0.05-0.05x)Zrx)O_(3)ceramics were fabricated using conventional solid-state reaction.Then,the phase structures,dielectric,ferroelectric,and...Heterovalent doped(K_(0.48-0.07)xNa_(0.52-0.43)xBi_(0.5)x)(Nb_(0.95-0.95x)Sb_(0.05-0.05x)Zrx)O_(3)ceramics were fabricated using conventional solid-state reaction.Then,the phase structures,dielectric,ferroelectric,and electricstrain properties were investigated.The compositions were tuned to be located at polymorphic phase boundary with increasing heterovalent Bi3t and Zr4t doping levels.A large strain of 0.19%was obtained at relatively low electric fields of 30 kV/cm in the composition of x=0.04.The normalized large-signal d33*values were approximately 633 pm/V under a low driving electric field of 30 kV/cm,which were comparable or larger than the values reported for other lead-free families.The large strains obtained can be attributed to the formation of nanodomains and high-density domain walls,which were confirmed by the observations of domain morphology using transmission electron microscopy(TEM)technique.Excellent temperature stability of the strain properties of the x=0.04 sample could be ascribed to the sluggish behaviour for the local structural heterogeneity in heterovalent-ion doped KNN ceramic.Theoretical simulations revealed that the Zr^(4t)produce the local stress at the BO6 octahedra and Bi3t could yield off-centering of AO12 ployhedron due to the nature of Bi 6s lone pair electrons,which induced lattice expansion and local distortions in the sample.The local displacements are strongly anisotropic in heterovalent-ion doped system.It is believed that random local fields exist in these compositions owing to the eixstence of charge distribution.Such heterovalent doping of Bi^(3t)and Zr^(4t)could destory simultaneously the orthorhombic symmetry and the short-range ferroelecctric order,leading to the formation of complex nanodomains and local structral hetergenenity.Heterovalent doping may,therefore,offer a new avenve to design novel K0.5Na0.5NbO3(KNN)-based materials for their mutifunctional applications.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2021YFA1200700)the National Natural Science Foundation of China(Grant Nos.T2222025 and 62174053)+5 种基金the Open Research Projects of Zhejiang Laboratory(Grant No.2021MD0AB03)the Shanghai Science and Technology Innovation Action Plan(Grant Nos.21JC1402000 and 21520714100)the Guangdong Provincial Key Laboratory Program(Grant No.2021B1212040001)the Fundamental Research Funds for the Central Universitiessupport from the Zuckerman STEM Leadership ProgramPazy Research Foundation(Grant No.149-2020)。
文摘Hafnium-based ferroelectric films,remaining their ferroelectricity down to nanoscale thickness,present a promising application for low-power logic devices and nonvolatile memories.It has been appealing for researchers to reduce the required temperature to obtain the ferroelectric phase in hafnium-based ferroelectric films for applications such as flexible and wearable electronics.This work demonstrates that a remanent polarization(P_(r))value of>5μC/cm^(2)can be obtained in asdeposited Hf_(0.5)Zr_(0.5)O_(2)(HZO)films that are fabricated by thermal atomic layer deposition(TALD)under low temperature of 250℃.The ferroelectric orthorhombic phase(o-phase)in the as-deposited HZO films is detected by scanning transmission electron microscopy(STEM).This low fabrication temperature further extends the compatibility of ferroelectric HZO films to flexible electronics and avoids the cost imposed by following high-temperature annealing treatments.
基金supported by National Key Research and Development Program of China(2021YFA1200700)The National Natural Science Foundation of China(T2222025 and 62174053)+2 种基金Open Research Projects of Zhejiang Lab(2021MD0AB03)Shanghai Science and Technology Innovation Action Plan(21JC1402000 and 21520714100)the Fundamental Research Funds for the Central Universities。
文摘In recent years,the emergence of numerous applications of artificial intelligence(AI)has sparked a new technological revolution.These applications include facial recognition,autonomous driving,intelligent robotics,and image restoration.However,the data processing and storage procedures in the conventional von Neumann architecture are discrete,which leads to the“memory wall”problem.As a result,such architecture is incompatible with AI requirements for efficient and sustainable processing.Exploring new computing architectures and material bases is therefore imperative.Inspired by neurobiological systems,in-memory and in-sensor computing techniques provide a new means of overcoming the limitations inherent in the von Neumann architecture.The basis of neural morphological computation is a crossbar array of high-density,high-efficiency non-volatile memory devices.Among the numerous candidate memory devices,ferroelectric memory devices with non-volatile polarization states,low power consumption and strong endurance are expected to be ideal candidates for neuromorphic computing.Further research on the complementary metal-oxide-semiconductor(CMOS)compatibility for these devices is underway and has yielded favorable results.Herein,we first introduce the development of ferroelectric materials as well as their mechanisms of polarization reversal and detail the applications of ferroelectric synaptic devices in artificial neural networks.Subsequently,we introduce the latest developments in ferroelectrics-based in-memory and in-sensor computing.Finally,we review recent works on hafnium-based ferroelectric memory devices with CMOS process compatibility and give a perspective for future developments.
基金supported by CAS Pioneer Hundred Talents Program(Y60707WR19)Zhejiang Province Qianjiang Talent Program(ZJ-QJRC-2020-32)+2 种基金the National Natural Science Foundation of China(51931011 and 52127803)K.C.Wong Education Foundation(GJTD-2020-11)“Pioneer”and“Leading Goose”R&D Program of Zhejiang(2022C01032)。
文摘Over the past two decades,flexible electronics have attracted numerous attentions for their potential use as flexible,stretchable,portable and conformable devices in various fields including computing,energy harvesting,robotics,sensors and transductors or health monitoring.
基金supported by National Science Foundation of China(NSFC No.52172125),the CSS project(YK2015-0602006),the Natural Science Foundation of Shandong Province of China(Grant No.ZR2018BA028),Quzhou Science and Technology Plan Project(2022K108)and General Research Project of Zhejiang Provincial Department of Education(Y202249978).
文摘Heterovalent doped(K_(0.48-0.07)xNa_(0.52-0.43)xBi_(0.5)x)(Nb_(0.95-0.95x)Sb_(0.05-0.05x)Zrx)O_(3)ceramics were fabricated using conventional solid-state reaction.Then,the phase structures,dielectric,ferroelectric,and electricstrain properties were investigated.The compositions were tuned to be located at polymorphic phase boundary with increasing heterovalent Bi3t and Zr4t doping levels.A large strain of 0.19%was obtained at relatively low electric fields of 30 kV/cm in the composition of x=0.04.The normalized large-signal d33*values were approximately 633 pm/V under a low driving electric field of 30 kV/cm,which were comparable or larger than the values reported for other lead-free families.The large strains obtained can be attributed to the formation of nanodomains and high-density domain walls,which were confirmed by the observations of domain morphology using transmission electron microscopy(TEM)technique.Excellent temperature stability of the strain properties of the x=0.04 sample could be ascribed to the sluggish behaviour for the local structural heterogeneity in heterovalent-ion doped KNN ceramic.Theoretical simulations revealed that the Zr^(4t)produce the local stress at the BO6 octahedra and Bi3t could yield off-centering of AO12 ployhedron due to the nature of Bi 6s lone pair electrons,which induced lattice expansion and local distortions in the sample.The local displacements are strongly anisotropic in heterovalent-ion doped system.It is believed that random local fields exist in these compositions owing to the eixstence of charge distribution.Such heterovalent doping of Bi^(3t)and Zr^(4t)could destory simultaneously the orthorhombic symmetry and the short-range ferroelecctric order,leading to the formation of complex nanodomains and local structral hetergenenity.Heterovalent doping may,therefore,offer a new avenve to design novel K0.5Na0.5NbO3(KNN)-based materials for their mutifunctional applications.
