This paper presents a comprehensive analysis of the short-circuit failure mechanisms in commercial 1.2 kV planar sili-con carbide(SiC)metal–oxide–semiconductor field-effect transistors(MOSFETs)under 400 and 800 V bu...This paper presents a comprehensive analysis of the short-circuit failure mechanisms in commercial 1.2 kV planar sili-con carbide(SiC)metal–oxide–semiconductor field-effect transistors(MOSFETs)under 400 and 800 V bus voltage conditions.The study compares two products with varying short-circuit tolerances,scrutinizing their external characteristics and intrinsic fac-tors that influence their short-circuit endurance.Experimental and numerical analyses reveal that at 400 V,the differential ther-mal expansion between the source metal and the dielectric leads to cracking,which in turn facilitates the infiltration of liquid metal and results in a gate–source short circuit.At 800 V,the failure mechanism is markedly different,attributed to the ther-mal carrier effect leading to the degradation of the gate oxide,which impedes the device's capacity to switch off,thereby trig-gering thermal runaway.The paper proposes strategies to augment the short-circuit robustness of SiC MOSFETs at both volt-age levels,with the objective of fortifying the device's resistance to such failures.展开更多
The expansive spectral coverage and superior optical properties of lithium niobate(LN)offer a comprehensive suite of tools for exploring novel functionalities.Achieving high-quality(Q)photonic resonator cavities is cr...The expansive spectral coverage and superior optical properties of lithium niobate(LN)offer a comprehensive suite of tools for exploring novel functionalities.Achieving high-quality(Q)photonic resonator cavities is crucial for enhancing light-matter interactions.However,this task is challenging as the device performance is heavily dependent on the fabrication quality of the LN.In this paper,we present experimental validation of an etchless approach to fabricating high-Q photonic crystal nanobeam cavities(PCNBCs).We successfully fabricate PCNBCs with Q factors exceeding 105 while maintaining high transmittance by capitalizing on the low waveguide loss and high fabrication tolerance of TE-polarized mode.Remarkably,the Q factor achieved here exceeds previous reports on etchless LN PCNBCs by over an order of magnitude.Benefiting from this advancement,we further explore a variety of optical functions,including thermo-optic tuning,optically induced bistability,and Fano line shapes generation.These findings present promising prospects for a versatile platform technique,facilitating the development of high-performance electro-optic or acousto-optic modulators,optical logic devices,and quantum photonics,highlighting its significant impact in the field of photonic integration.展开更多
The performance enhancement of conventional Si MOSFETs through device scaling is becoming increasingly difficult.The application of high mobility channel materials is one of the most promising solutions to overcome th...The performance enhancement of conventional Si MOSFETs through device scaling is becoming increasingly difficult.The application of high mobility channel materials is one of the most promising solutions to overcome the bottleneck.The Ge and GeSn channels attract a lot of interest as the alternative channel materials,not only because of the high carrier mobility but also the superior compatibility with typical Si CMOS technology.In this paper,the recent progress of high mobility Ge and GeSn MOSFETs has been investigated,providing feasible approaches to improve the performance of Ge and GeSn devices for future CMOS technologies.展开更多
Controlling the epitaxial growth mode of semiconductor layers is crucial for optimizing material properties and device performance.In this work,the growth mode ofα-Ga_(2)O_(3) heteroepitaxial layers was modulated by ...Controlling the epitaxial growth mode of semiconductor layers is crucial for optimizing material properties and device performance.In this work,the growth mode ofα-Ga_(2)O_(3) heteroepitaxial layers was modulated by tuning miscut angles(θ)from 0°to 7°off the(1010)direction of sapphire(0002)substrate.On flat sapphire surfaces,the growth undergoes a typical three-dimensional(3D)growth mode due to the random nucleation on wide substrate terraces,as evidenced by the hillock morphology and high dislocation densities.As the miscut angle increases toθ=5°,the terrace width of sapphire substrate is comparable to the distance between neighboring nuclei,and consequently,the nucleation is guided by terrace edges,which energetically facilitates the growth mode transition into the desirable two-dimensional(2D)coherent growth.Consequently,the mean surface roughness decreases to only 0.62 nm,accompanied by a significant reduction in screw and edge dislocations to 0.16×10^(7) cm^(-2)and 3.58×10^(9) cm^(-2),respectively.However,the further increment of miscut angles toθ=7°shrink the terrace width less than nucleation distance,and the step-bunching growth mode is dominant.In this circumstance,the misfit strain is released in the initial growth stage,resulting in surface morphology degradation and increased dislocation densities.展开更多
Hafnium zirconium oxides(HZO),which exhibit ferroelectric properties,are promising materials for nanoscale device fabrication due to their high complementary metal-oxide-semiconductor(CMOS) compatibility.In addition t...Hafnium zirconium oxides(HZO),which exhibit ferroelectric properties,are promising materials for nanoscale device fabrication due to their high complementary metal-oxide-semiconductor(CMOS) compatibility.In addition to piezoelectricity,ferroelectricity,and flexoelectricity,this study reports the observation of ferroelasticity using piezoelectric force microscopy(PFM) and scanning transmission electron microscopy(STEM).The dynamics of 90° ferroelastic domains in HZO thin films are investigated under the influence of an electric field.Switching of the retentive domains is observed through repeated wake-up measurements.This study presents a possibility of enhancing polarization in HZO thin films during wake-up processes.展开更多
The explosive growth of data and information has motivated various emerging non-von Neumann computational approaches in the More-than-Moore era.Photonics neuromorphic computing has attracted lots of attention due to t...The explosive growth of data and information has motivated various emerging non-von Neumann computational approaches in the More-than-Moore era.Photonics neuromorphic computing has attracted lots of attention due to the fascinating advantages such as high speed,wide bandwidth,and massive parallelism.Here,we offer a review on the optical neural computing in our research groups at the device and system levels.The photonics neuron and photonics synapse plasticity are presented.In addition,we introduce several optical neural computing architectures and algorithms including photonic spiking neural network,photonic convolutional neural network,photonic matrix computation,photonic reservoir computing,and photonic reinforcement learning.Finally,we summarize the major challenges faced by photonic neuromorphic computing,and propose promising solutions and perspectives.展开更多
The realization of high-Q resonances in a silicon metasurface with various broken-symmetry blocks is reported. Theoretical analysis reveals that the sharp resonances in the metasurfaces originate from symmetry-protect...The realization of high-Q resonances in a silicon metasurface with various broken-symmetry blocks is reported. Theoretical analysis reveals that the sharp resonances in the metasurfaces originate from symmetry-protected bound in the continuum(BIC) and the magnetic dipole dominates these peculiar states. A smaller size of the defect in the broken-symmetry block gives rise to the resonance with a larger Q factor. Importantly, this relationship can be tuned by changing the structural parameter, resulting from the modulation of the topological configuration of BICs. Consequently, a Q factor of more than 3,000 can be easily achieved by optimizing dimensions of the nanostructure. At this sharp resonance, the intensity of the third harmonic generation signal in the patterned structure can be 368 times larger than that of the flat silicon film. The proposed strategy and underlying theory can open up new avenues to realize ultrasharp resonances, which may promote the development of the potential meta-devices for nonlinearity, lasing action, and sensing.展开更多
Over the past half century,Moore’s Law has played a crucial role in the development of the semiconductor field,which depends on straightforwardly dimensional scaling with approximately a two-year cadence.Significant ...Over the past half century,Moore’s Law has played a crucial role in the development of the semiconductor field,which depends on straightforwardly dimensional scaling with approximately a two-year cadence.Significant benefits of performance,power,area,and cost(PPAC)in microchips are expected at each technology node.However,aggressive pitchbased scaling by resolution enhancement techniques becomes increasingly challenging to sustain.展开更多
Traditional charge-based memories,such as dynamic random-access memory(DRAM)and flash,are approaching their scaling limits.A variety of resistance-based memories,such as phase-change memory(PCM),magnetic random-access...Traditional charge-based memories,such as dynamic random-access memory(DRAM)and flash,are approaching their scaling limits.A variety of resistance-based memories,such as phase-change memory(PCM),magnetic random-access memory(MRAM)and resistive random-access memory(RRAM),have been long considered for emerging memory applications thanks to their non-volatility,fast speed,low power,and compact size for potentially high-density integration.展开更多
In the past few decades,the Moore’s Law has been the revolutionary force for our integrated circuit(IC)industry.However,the tremendous challenges faced in continuous transistor physical down-scaling and the unprecede...In the past few decades,the Moore’s Law has been the revolutionary force for our integrated circuit(IC)industry.However,the tremendous challenges faced in continuous transistor physical down-scaling and the unprecedented demands for computing and storage capabilities require our urgent search for strategies and solutions to integrate diverse materials,devices,circuits,and architectures in a 3D vertically stacked manner so that they can orchestrate in the most effective way to provide significantly enhanced functionalities as well as superior speed,energy,bandwidth,form fact,and cost.展开更多
The more severe phonon-phonon scattering in gallium oxide(Ga_(2)O_(3)) crystals leads to lower thermal conductivity compared to most other semiconductor materials. To address this issue and enhance the heat dissipatio...The more severe phonon-phonon scattering in gallium oxide(Ga_(2)O_(3)) crystals leads to lower thermal conductivity compared to most other semiconductor materials. To address this issue and enhance the heat dissipation in Ga_(2)O_(3) devices, one practical solution is to integrate Ga_(2)O_(3) with a highly thermally conductive substrate, such as SiC and Si. Currently,there are three methods employed for the heterogeneous integration of Ga_(2)O_(3) with highly thermally conductive substrates:mechanical exfoliation, hetero-epitaxy growth, and ion-cutting technique.展开更多
There is currently great optimism within the electronics community that gallium oxide(Ga_(2)O_(3)) ultra-wide bandgap semiconductors have unprecedented prospects for eventually revolutionizing a rich variety of power ...There is currently great optimism within the electronics community that gallium oxide(Ga_(2)O_(3)) ultra-wide bandgap semiconductors have unprecedented prospects for eventually revolutionizing a rich variety of power electronic applications. Specially, benefiting from its ultra-high bandgap of around 4.8 eV, it is expected that the emerging Ga_(2)O_(3) technology would offer an exciting platform to deliver massively enhanced device performance for power electronics and even completely new applications.展开更多
Gallium oxide(Ga_(2)O_(3))has garnered world-wide atten-tion as an ultrawide-bandgap semiconductor material from the area of power electronics and DUV optical devices benefit-ing from its outstanding electronic and op...Gallium oxide(Ga_(2)O_(3))has garnered world-wide atten-tion as an ultrawide-bandgap semiconductor material from the area of power electronics and DUV optical devices benefit-ing from its outstanding electronic and optoelectronic proper-ties.For one thing,since Ga_(2)O_(3)features high critical break-down field of 8 MV/cm and Baliga’s figure of merit(BFOM)of 3444,it is a promising candidate for advanced high-power applications.For another thing,due to the bandgap directly corresponding to the deep-ultraviolet(DUV)region,Ga_(2)O_(3)is widely used in DUV optoelectronic devices.展开更多
We summarize our work of the optoelectronic devices based on Germanium-tin （GeSn） alloys assisted with the Si3N4liner stressor in mid-infrared （MIR） domains. The device characteristics are thoroughly analyzed by t...We summarize our work of the optoelectronic devices based on Germanium-tin （GeSn） alloys assisted with the Si3N4liner stressor in mid-infrared （MIR） domains. The device characteristics are thoroughly analyzed by the strain distribution,band structure, and absorption characteristics. Numerical and analytical methods show that with optimal structural pa-rameters, the device performance can be further improved and the wavelength application range can be extended to 2~5 μm in the mid-infrared spectra. It is demonstrated that this proposed strategy provides an effective technique for the strained-GeSn devices in future optical designs, which will be competitive for the optoelectronics applications in mid-infrared wavelength.展开更多
The wide-bandgap semiconductor material Ga_(2)O_(3) exhibits great potential in solar-blind deep-ultraviolet(DUV)photodetection applications,including none-line-of-sight secure optical communication,fire warning,high-...The wide-bandgap semiconductor material Ga_(2)O_(3) exhibits great potential in solar-blind deep-ultraviolet(DUV)photodetection applications,including none-line-of-sight secure optical communication,fire warning,high-voltage electricity monitoring,and maritime fog dispersion navigation.However,Ga_(2)O_(3) photodetectors have traditionally faced challenges in achieving both high responsivity and fast response time,limiting their practical application.Herein,the Ga_(2)O_(3) solar-blind DUV photodetectors with a suspended structure have been constructed for the first time.The photodetector exhibits a high responsivity of 1.51×10^(10) A/W,a sensitive detectivity of 6.01×10^(17) Jones,a large external quantum efficiency of 7.53×10^(12)%,and a fast rise time of 180 ms under 250-nm illumination.Notably,the photodetector achieves both high responsivity and fast response time simultaneously under ultra-weak power intensity excitation of 0.01μW/cm^(2).This important improvement is attributed to the reduction of interface defects,improved carrier transport,efficient carrier separation,and enhanced light absorption enabled by the suspended structure.This work provides valuable insights for designing and optimizing high-performance Ga_(2)O_(3) solar-blind photodetectors.展开更多
Due to its high critical breakdown electrical field and the availability of large-scale single crystal substrates,Gallium oxide(Ga_(2)O_(3))holds great promise for power electronic and radio frequency(RF)applications....Due to its high critical breakdown electrical field and the availability of large-scale single crystal substrates,Gallium oxide(Ga_(2)O_(3))holds great promise for power electronic and radio frequency(RF)applications.While significant advancements have been made in Ga_(2)O_(3)material and device research,there are still challenges related to its ultra-low thermal conductivity and the lack of effective p-type doping methods.These limitations hinder the fabrication of complex device structures and the enhancement of device performance.This review aims to provide an introduction to the research development of Ga_(2)O_(3)heterogeneous and heterojunction power devices based on heterogeneous integration technology.By utilizing ion-cutting and wafer bonding techniques,heterogeneous substrates with high thermal conductivity have been realized,offering a viable solution to overcome the thermal limitations of Ga_(2)O_(3).Compared to Ga_(2)O_(3)bulk devices,Ga_(2)O_(3)devices fabricated on heterogeneous substrates integrated with SiC or Si exhibit superior thermal properties.Power diodes and superjunction transistors based on p-NiO/n-Ga_(2)O_(3)heterojunctions on heterogeneous substrates have demonstrated outstanding electrical characteristics,presenting a feasible method for the development of bipolar devices.The technologies of heterogeneous integration and heterojunction address critical issues related to Ga_(2)O_(3),thereby advancing the commercial applications of Ga_(2)O_(3)devices in power and RF fields.By integrating Ga_(2)O_(3)with other materials and leveraging heterojunction interfaces,researchers and engineers have made significant progress in improving device performance and overcoming limitations.These advancements pave the way for the wider adoption of Ga_(2)O_(3)-based devices in various power and RF applications.展开更多
The discovery of ferroelectricity in aluminum scandium nitride(AlScN)thin films has garnered significant research inter-est,owing to the large remnant polarization,tunable coercive field,excellent thermal stability,hi...The discovery of ferroelectricity in aluminum scandium nitride(AlScN)thin films has garnered significant research inter-est,owing to the large remnant polarization,tunable coercive field,excellent thermal stability,high breakdown field,and compatibility with back-end-of-line processes of these thin films.These attributes make AlScN a highly promising can-didate for next-generation electronic device applications.Various techniques,such as reactive magnetron sputtering,radi-ofrequency sputtering,molecular beam epitaxy,metal-organic chemical vapor deposition,and pulsed laser deposition,have been employed to grow ferroelectric AlScN thin films.Critical growth parameters,including deposition atmosphere,precursor selection,and Sc concentration,strongly influence the ferroelectric properties,playing a crucial role in achieving high crystalline quality.This review critically examines the fabrication techniques used for producing ferroelectric AlScN thin films,focusing on the impact of different growth methods and process conditions on their properties.We aim to provide comprehensive guidance to assist future researchers in optimizing their process parameters to achieve the desired ferroelectric characteristics in AlScN thin films.展开更多
Two-dimensional(2D)materials that combine ferromagnetic,semiconductor,and piezoelectric properties hold significant potential for both fundamental research and spin electronic devices.However,the majority of reported ...Two-dimensional(2D)materials that combine ferromagnetic,semiconductor,and piezoelectric properties hold significant potential for both fundamental research and spin electronic devices.However,the majority of reported 2D ferromagnetic-semiconductor-piezoelectric materials rely on d-electron systems,which limits their practical applications due to a Curie temperature lower than room temperature(RT).Here,we report a high-crystallinity carbon nitride(CCN)material based on sp-electrons using a chemical vapor deposition strategy.CCN exhibits a band gap of 1.8 eV and has been confirmed to possess substantial in-plane and out-of-plane piezoelectricity.Moreover,we acquired clear evidences of ferromagnetic behavior at room temperature.Extensive structural characterizations combined with theoretical calculations reveal that incorporating structural oxygen into the highly ordered heptazine structure causes partial substitution of nitrogen sites,which is primarily responsible for generating room-temperature ferromagnetism and piezoelectricity.As a result,the strain in wrinkles can effectively modulate the domain behavior and piezoelectric potential at room temperature.The addition of RT ferromagnetic-semiconductor-piezoelectric material based on sp-electrons to the family of two-dimensional materials opens up numerous possibilities for novel applications in fundamental research and spin electronic devices.展开更多
Ferroelectric HfO_(2)-based materials and devices show promising potential for applications in information technology but face challenges with inadequate electrostatic control,degraded reliability,and serious variatio...Ferroelectric HfO_(2)-based materials and devices show promising potential for applications in information technology but face challenges with inadequate electrostatic control,degraded reliability,and serious variation in effective oxide thickness scaling.We demonstrate a novel interface-type switching strategy to realize ferroelectric characteristics in atomic-scale amorphous binary oxide films,which are formed in oxygen-deficient conditions by atomic layer deposition at low temperatures.This approach can avoid the shortcomings of reliability degradation and gate leakage increment in scaling polycrystalline doped HfO_(2)-based films.Using theoretical modeling and experimental characterization,we show the following.(1)Emerging ferroelectricity exists in ultrathin oxide systems as a result of microscopic ion migration during the switching process.(2)These ferroelectric binary oxide films are governed by an interface-limited switching mechanism,which can be attributed to oxygen vacancy migration and surface defects related to electron(de)trapping.(3)Transistors featuring ultrathin amorphous dielectrics,used for non-volatile memory applications with an operating voltage reduced to±1 V,have also been experimentally demonstrated.These findings suggest that this strategy is a promising approach to realizing next-generation complementary metal-oxide semiconductors with scalable ferroelectric materials.展开更多
With major signal analytical elements situated away from the measurement environment,extended gate(EG)ion-sensitive fieldeffect transistors(ISFETs)offer prospects for whole chip circuit design and system integration o...With major signal analytical elements situated away from the measurement environment,extended gate(EG)ion-sensitive fieldeffect transistors(ISFETs)offer prospects for whole chip circuit design and system integration of chemical sensors.In this work,a highly sensitive and power-efficient ISFET was proposed based on a metal-ferroelectric-insulator gate stack with negative capacitance–induced super-steep subthreshold swing and ferroelectric memory function.Along with a remotely connected EG electrode,the architecture facilitates diverse sensing functions for future establishment of smart biochemical sensor platforms.展开更多
基金supported by the Science and Technology Innovation Key R&D Program of Chongqing (Grant No.2023TIADSTX0037)the National Natural Science Foundation of China (Grant No.62404026)+1 种基金the General Program of National Natural Science Foundation of Chongqing (Grant Nos.CSTB2023NSCQ-MSX0475,CSTB2024NSCQ-MSX0331)the Science and Technology Research Program of Chongqing Municipal Education Commission (Grant No.KJQN202400609).
文摘This paper presents a comprehensive analysis of the short-circuit failure mechanisms in commercial 1.2 kV planar sili-con carbide(SiC)metal–oxide–semiconductor field-effect transistors(MOSFETs)under 400 and 800 V bus voltage conditions.The study compares two products with varying short-circuit tolerances,scrutinizing their external characteristics and intrinsic fac-tors that influence their short-circuit endurance.Experimental and numerical analyses reveal that at 400 V,the differential ther-mal expansion between the source metal and the dielectric leads to cracking,which in turn facilitates the infiltration of liquid metal and results in a gate–source short circuit.At 800 V,the failure mechanism is markedly different,attributed to the ther-mal carrier effect leading to the degradation of the gate oxide,which impedes the device's capacity to switch off,thereby trig-gering thermal runaway.The paper proposes strategies to augment the short-circuit robustness of SiC MOSFETs at both volt-age levels,with the objective of fortifying the device's resistance to such failures.
基金the National Key R&D Program of China(No.2022ZD0119002)the National Natural Science Foundation of China(Grant No.62025402,62090033,92364204,92264202 and 62293522)Major Program of Zhejiang Natural Science Foundation(Grant No.LDT23F04024F04)。
文摘The expansive spectral coverage and superior optical properties of lithium niobate(LN)offer a comprehensive suite of tools for exploring novel functionalities.Achieving high-quality(Q)photonic resonator cavities is crucial for enhancing light-matter interactions.However,this task is challenging as the device performance is heavily dependent on the fabrication quality of the LN.In this paper,we present experimental validation of an etchless approach to fabricating high-Q photonic crystal nanobeam cavities(PCNBCs).We successfully fabricate PCNBCs with Q factors exceeding 105 while maintaining high transmittance by capitalizing on the low waveguide loss and high fabrication tolerance of TE-polarized mode.Remarkably,the Q factor achieved here exceeds previous reports on etchless LN PCNBCs by over an order of magnitude.Benefiting from this advancement,we further explore a variety of optical functions,including thermo-optic tuning,optically induced bistability,and Fano line shapes generation.These findings present promising prospects for a versatile platform technique,facilitating the development of high-performance electro-optic or acousto-optic modulators,optical logic devices,and quantum photonics,highlighting its significant impact in the field of photonic integration.
基金This work was supported,in part,by the Zhejiang Provincial Natural Science Foundation of China under Grant LR18F040001the Fundamental Research Funds for the Central Universities。
文摘The performance enhancement of conventional Si MOSFETs through device scaling is becoming increasingly difficult.The application of high mobility channel materials is one of the most promising solutions to overcome the bottleneck.The Ge and GeSn channels attract a lot of interest as the alternative channel materials,not only because of the high carrier mobility but also the superior compatibility with typical Si CMOS technology.In this paper,the recent progress of high mobility Ge and GeSn MOSFETs has been investigated,providing feasible approaches to improve the performance of Ge and GeSn devices for future CMOS technologies.
基金Project supported by the National Key Research and Development Program of China (Grant No.2022YFB3605403)the National Natural Science Foundation of China (Grant Nos.62234007,62241407,62293521,62304238,62241407,U21A20503,and U21A2071)+2 种基金the Key-Area Research and Development Program of Guangdong Province,China (Grant No.2020B010174002)the Cultivation Project for Youth Teachers in Jiangsu ProvinceJiangsu Funding Program for Excellent Postdoctoral Talent。
文摘Controlling the epitaxial growth mode of semiconductor layers is crucial for optimizing material properties and device performance.In this work,the growth mode ofα-Ga_(2)O_(3) heteroepitaxial layers was modulated by tuning miscut angles(θ)from 0°to 7°off the(1010)direction of sapphire(0002)substrate.On flat sapphire surfaces,the growth undergoes a typical three-dimensional(3D)growth mode due to the random nucleation on wide substrate terraces,as evidenced by the hillock morphology and high dislocation densities.As the miscut angle increases toθ=5°,the terrace width of sapphire substrate is comparable to the distance between neighboring nuclei,and consequently,the nucleation is guided by terrace edges,which energetically facilitates the growth mode transition into the desirable two-dimensional(2D)coherent growth.Consequently,the mean surface roughness decreases to only 0.62 nm,accompanied by a significant reduction in screw and edge dislocations to 0.16×10^(7) cm^(-2)and 3.58×10^(9) cm^(-2),respectively.However,the further increment of miscut angles toθ=7°shrink the terrace width less than nucleation distance,and the step-bunching growth mode is dominant.In this circumstance,the misfit strain is released in the initial growth stage,resulting in surface morphology degradation and increased dislocation densities.
基金Project supported by the the National Key Research and Development Program of China (Grant No. 2022YFA1402902)the National Natural Science Foundation of China (Grant Nos. 12074119, 12204171, 12134003, and 12374145)+1 种基金the Chenguang Program Foundation of Shanghai Education Development Foundation and Shanghai Municipal Education Commission, ECNU (East China Normal University) Multifunctional Platform for Innovation (006)the Fundamental Research Funds for the Central Universities。
文摘Hafnium zirconium oxides(HZO),which exhibit ferroelectric properties,are promising materials for nanoscale device fabrication due to their high complementary metal-oxide-semiconductor(CMOS) compatibility.In addition to piezoelectricity,ferroelectricity,and flexoelectricity,this study reports the observation of ferroelasticity using piezoelectric force microscopy(PFM) and scanning transmission electron microscopy(STEM).The dynamics of 90° ferroelastic domains in HZO thin films are investigated under the influence of an electric field.Switching of the retentive domains is observed through repeated wake-up measurements.This study presents a possibility of enhancing polarization in HZO thin films during wake-up processes.
基金This work was supported in part by the National Outstanding Youth Science Fund Project of National Natural Science Foundation of China(62022062)the National Natural Science Foundation of China(61974177,61674119)the Fundamental Research Funds for the Central Universities.
文摘The explosive growth of data and information has motivated various emerging non-von Neumann computational approaches in the More-than-Moore era.Photonics neuromorphic computing has attracted lots of attention due to the fascinating advantages such as high speed,wide bandwidth,and massive parallelism.Here,we offer a review on the optical neural computing in our research groups at the device and system levels.The photonics neuron and photonics synapse plasticity are presented.In addition,we introduce several optical neural computing architectures and algorithms including photonic spiking neural network,photonic convolutional neural network,photonic matrix computation,photonic reservoir computing,and photonic reinforcement learning.Finally,we summarize the major challenges faced by photonic neuromorphic computing,and propose promising solutions and perspectives.
基金support from the National Key Research and Development Project (Grant No. 2018YFB2200500, 2018YFB2202800)National Natural Science Foundation of China (Grant No. 61534004, 91964202, 61874081, 61851406, 91950119, and 61905196)。
文摘The realization of high-Q resonances in a silicon metasurface with various broken-symmetry blocks is reported. Theoretical analysis reveals that the sharp resonances in the metasurfaces originate from symmetry-protected bound in the continuum(BIC) and the magnetic dipole dominates these peculiar states. A smaller size of the defect in the broken-symmetry block gives rise to the resonance with a larger Q factor. Importantly, this relationship can be tuned by changing the structural parameter, resulting from the modulation of the topological configuration of BICs. Consequently, a Q factor of more than 3,000 can be easily achieved by optimizing dimensions of the nanostructure. At this sharp resonance, the intensity of the third harmonic generation signal in the patterned structure can be 368 times larger than that of the flat silicon film. The proposed strategy and underlying theory can open up new avenues to realize ultrasharp resonances, which may promote the development of the potential meta-devices for nonlinearity, lasing action, and sensing.
文摘Over the past half century,Moore’s Law has played a crucial role in the development of the semiconductor field,which depends on straightforwardly dimensional scaling with approximately a two-year cadence.Significant benefits of performance,power,area,and cost(PPAC)in microchips are expected at each technology node.However,aggressive pitchbased scaling by resolution enhancement techniques becomes increasingly challenging to sustain.
文摘Traditional charge-based memories,such as dynamic random-access memory(DRAM)and flash,are approaching their scaling limits.A variety of resistance-based memories,such as phase-change memory(PCM),magnetic random-access memory(MRAM)and resistive random-access memory(RRAM),have been long considered for emerging memory applications thanks to their non-volatility,fast speed,low power,and compact size for potentially high-density integration.
文摘In the past few decades,the Moore’s Law has been the revolutionary force for our integrated circuit(IC)industry.However,the tremendous challenges faced in continuous transistor physical down-scaling and the unprecedented demands for computing and storage capabilities require our urgent search for strategies and solutions to integrate diverse materials,devices,circuits,and architectures in a 3D vertically stacked manner so that they can orchestrate in the most effective way to provide significantly enhanced functionalities as well as superior speed,energy,bandwidth,form fact,and cost.
文摘The more severe phonon-phonon scattering in gallium oxide(Ga_(2)O_(3)) crystals leads to lower thermal conductivity compared to most other semiconductor materials. To address this issue and enhance the heat dissipation in Ga_(2)O_(3) devices, one practical solution is to integrate Ga_(2)O_(3) with a highly thermally conductive substrate, such as SiC and Si. Currently,there are three methods employed for the heterogeneous integration of Ga_(2)O_(3) with highly thermally conductive substrates:mechanical exfoliation, hetero-epitaxy growth, and ion-cutting technique.
文摘There is currently great optimism within the electronics community that gallium oxide(Ga_(2)O_(3)) ultra-wide bandgap semiconductors have unprecedented prospects for eventually revolutionizing a rich variety of power electronic applications. Specially, benefiting from its ultra-high bandgap of around 4.8 eV, it is expected that the emerging Ga_(2)O_(3) technology would offer an exciting platform to deliver massively enhanced device performance for power electronics and even completely new applications.
文摘Gallium oxide(Ga_(2)O_(3))has garnered world-wide atten-tion as an ultrawide-bandgap semiconductor material from the area of power electronics and DUV optical devices benefit-ing from its outstanding electronic and optoelectronic proper-ties.For one thing,since Ga_(2)O_(3)features high critical break-down field of 8 MV/cm and Baliga’s figure of merit(BFOM)of 3444,it is a promising candidate for advanced high-power applications.For another thing,due to the bandgap directly corresponding to the deep-ultraviolet(DUV)region,Ga_(2)O_(3)is widely used in DUV optoelectronic devices.
基金The authors thank National Natural Science Foundation of China （Grant No. 61534004, 61604112 and 61622405）.
文摘We summarize our work of the optoelectronic devices based on Germanium-tin （GeSn） alloys assisted with the Si3N4liner stressor in mid-infrared （MIR） domains. The device characteristics are thoroughly analyzed by the strain distribution,band structure, and absorption characteristics. Numerical and analytical methods show that with optimal structural pa-rameters, the device performance can be further improved and the wavelength application range can be extended to 2~5 μm in the mid-infrared spectra. It is demonstrated that this proposed strategy provides an effective technique for the strained-GeSn devices in future optical designs, which will be competitive for the optoelectronics applications in mid-infrared wavelength.
基金support from the China Postdoctoral Science Foundation(2023M742732)the Postdoctoral Fellowship Program of CPSF under grant number GZC20241303+3 种基金the Fundamental Research Funds for the Central Universities(XJSJ24100)the National Key R&D Program of China(2023YFB4402303)the National Natural Science Foundation of China(grant nos.62404176,62025402,62090033,92364204,9226420,and 62293522)Major Program of Zhejiang Natural Science Foundation(grant no.LDT23F04024F04).
文摘The wide-bandgap semiconductor material Ga_(2)O_(3) exhibits great potential in solar-blind deep-ultraviolet(DUV)photodetection applications,including none-line-of-sight secure optical communication,fire warning,high-voltage electricity monitoring,and maritime fog dispersion navigation.However,Ga_(2)O_(3) photodetectors have traditionally faced challenges in achieving both high responsivity and fast response time,limiting their practical application.Herein,the Ga_(2)O_(3) solar-blind DUV photodetectors with a suspended structure have been constructed for the first time.The photodetector exhibits a high responsivity of 1.51×10^(10) A/W,a sensitive detectivity of 6.01×10^(17) Jones,a large external quantum efficiency of 7.53×10^(12)%,and a fast rise time of 180 ms under 250-nm illumination.Notably,the photodetector achieves both high responsivity and fast response time simultaneously under ultra-weak power intensity excitation of 0.01μW/cm^(2).This important improvement is attributed to the reduction of interface defects,improved carrier transport,efficient carrier separation,and enhanced light absorption enabled by the suspended structure.This work provides valuable insights for designing and optimizing high-performance Ga_(2)O_(3) solar-blind photodetectors.
基金supported by grants from the National Natural Science Foundation of China(62293522,62293521,62204255 and 62234007).
文摘Due to its high critical breakdown electrical field and the availability of large-scale single crystal substrates,Gallium oxide(Ga_(2)O_(3))holds great promise for power electronic and radio frequency(RF)applications.While significant advancements have been made in Ga_(2)O_(3)material and device research,there are still challenges related to its ultra-low thermal conductivity and the lack of effective p-type doping methods.These limitations hinder the fabrication of complex device structures and the enhancement of device performance.This review aims to provide an introduction to the research development of Ga_(2)O_(3)heterogeneous and heterojunction power devices based on heterogeneous integration technology.By utilizing ion-cutting and wafer bonding techniques,heterogeneous substrates with high thermal conductivity have been realized,offering a viable solution to overcome the thermal limitations of Ga_(2)O_(3).Compared to Ga_(2)O_(3)bulk devices,Ga_(2)O_(3)devices fabricated on heterogeneous substrates integrated with SiC or Si exhibit superior thermal properties.Power diodes and superjunction transistors based on p-NiO/n-Ga_(2)O_(3)heterojunctions on heterogeneous substrates have demonstrated outstanding electrical characteristics,presenting a feasible method for the development of bipolar devices.The technologies of heterogeneous integration and heterojunction address critical issues related to Ga_(2)O_(3),thereby advancing the commercial applications of Ga_(2)O_(3)devices in power and RF fields.By integrating Ga_(2)O_(3)with other materials and leveraging heterojunction interfaces,researchers and engineers have made significant progress in improving device performance and overcoming limitations.These advancements pave the way for the wider adoption of Ga_(2)O_(3)-based devices in various power and RF applications.
基金supported by the China Postdoctoral Science Foundation(2023M742732)the Postdoctoral Fellowship Program of CPSF under(Grant No.GZC20241303)+2 种基金the Fundamental Research Funds for the Central Universities(XJSJ24100)the National Natural Science Foundation of China(Grant Nos.62404176,62025402,62090033,92364204,9226420,and 62293522)Major Program of Zhejiang Natural Science Foundation(Grant No.LDT23F04024F04).
文摘The discovery of ferroelectricity in aluminum scandium nitride(AlScN)thin films has garnered significant research inter-est,owing to the large remnant polarization,tunable coercive field,excellent thermal stability,high breakdown field,and compatibility with back-end-of-line processes of these thin films.These attributes make AlScN a highly promising can-didate for next-generation electronic device applications.Various techniques,such as reactive magnetron sputtering,radi-ofrequency sputtering,molecular beam epitaxy,metal-organic chemical vapor deposition,and pulsed laser deposition,have been employed to grow ferroelectric AlScN thin films.Critical growth parameters,including deposition atmosphere,precursor selection,and Sc concentration,strongly influence the ferroelectric properties,playing a crucial role in achieving high crystalline quality.This review critically examines the fabrication techniques used for producing ferroelectric AlScN thin films,focusing on the impact of different growth methods and process conditions on their properties.We aim to provide comprehensive guidance to assist future researchers in optimizing their process parameters to achieve the desired ferroelectric characteristics in AlScN thin films.
基金the National Key R&D Program of China(No.2022ZD0119002)the National Natural Science Foundation of China(Nos.62025402,62090033,91964202,92064003,92264202,62293522,12104352,and 12204294)+3 种基金the Major Program of Zhejiang Natural Science Foundation(No.DT23F0402)the Fundamental Research Funds for the Central Universities(Nos.QTZX23040 and QTZX23079)the China National Postdoctoral Programme for Innovative Talents(No.BX20230281)the Natural Science Basic Research Program of Shaanxi(No.2023JC-XJ-01).
文摘Two-dimensional(2D)materials that combine ferromagnetic,semiconductor,and piezoelectric properties hold significant potential for both fundamental research and spin electronic devices.However,the majority of reported 2D ferromagnetic-semiconductor-piezoelectric materials rely on d-electron systems,which limits their practical applications due to a Curie temperature lower than room temperature(RT).Here,we report a high-crystallinity carbon nitride(CCN)material based on sp-electrons using a chemical vapor deposition strategy.CCN exhibits a band gap of 1.8 eV and has been confirmed to possess substantial in-plane and out-of-plane piezoelectricity.Moreover,we acquired clear evidences of ferromagnetic behavior at room temperature.Extensive structural characterizations combined with theoretical calculations reveal that incorporating structural oxygen into the highly ordered heptazine structure causes partial substitution of nitrogen sites,which is primarily responsible for generating room-temperature ferromagnetism and piezoelectricity.As a result,the strain in wrinkles can effectively modulate the domain behavior and piezoelectric potential at room temperature.The addition of RT ferromagnetic-semiconductor-piezoelectric material based on sp-electrons to the family of two-dimensional materials opens up numerous possibilities for novel applications in fundamental research and spin electronic devices.
基金support from the National Key R&D Program of China(No.2022ZD0119002)the National Natural Science Foundation of China(Grant Nos.62204226,62025402,62090033,92364204,92264202 and 62293522)Major Program of Zhejiang Natural Science Foundation(Grant No.LDT23F04024F04).
文摘Ferroelectric HfO_(2)-based materials and devices show promising potential for applications in information technology but face challenges with inadequate electrostatic control,degraded reliability,and serious variation in effective oxide thickness scaling.We demonstrate a novel interface-type switching strategy to realize ferroelectric characteristics in atomic-scale amorphous binary oxide films,which are formed in oxygen-deficient conditions by atomic layer deposition at low temperatures.This approach can avoid the shortcomings of reliability degradation and gate leakage increment in scaling polycrystalline doped HfO_(2)-based films.Using theoretical modeling and experimental characterization,we show the following.(1)Emerging ferroelectricity exists in ultrathin oxide systems as a result of microscopic ion migration during the switching process.(2)These ferroelectric binary oxide films are governed by an interface-limited switching mechanism,which can be attributed to oxygen vacancy migration and surface defects related to electron(de)trapping.(3)Transistors featuring ultrathin amorphous dielectrics,used for non-volatile memory applications with an operating voltage reduced to±1 V,have also been experimentally demonstrated.These findings suggest that this strategy is a promising approach to realizing next-generation complementary metal-oxide semiconductors with scalable ferroelectric materials.
基金the National Natural Science Foundation of China No.52073160the National Key Research and Development Program of China No.2020YFF01014706+1 种基金Beijing Municipal Science and Technology Commission(Z211100002421012)Key Laboratory of Advanced Materials(MOE).
文摘With major signal analytical elements situated away from the measurement environment,extended gate(EG)ion-sensitive fieldeffect transistors(ISFETs)offer prospects for whole chip circuit design and system integration of chemical sensors.In this work,a highly sensitive and power-efficient ISFET was proposed based on a metal-ferroelectric-insulator gate stack with negative capacitance–induced super-steep subthreshold swing and ferroelectric memory function.Along with a remotely connected EG electrode,the architecture facilitates diverse sensing functions for future establishment of smart biochemical sensor platforms.
