Reducing the process variation is a significant concern for resistive random access memory(RRAM).Due to its ultrahigh integration density,RRAM arrays are prone to lithographic variation during the lithography process,...Reducing the process variation is a significant concern for resistive random access memory(RRAM).Due to its ultrahigh integration density,RRAM arrays are prone to lithographic variation during the lithography process,introducing electrical variation among different RRAM devices.In this work,an optical physical verification methodology for the RRAM array is developed,and the effects of different layout parameters on important electrical characteristics are systematically investigated.The results indicate that the RRAM devices can be categorized into three clusters according to their locations and lithography environments.The read resistance is more sensitive to the locations in the array(~30%)than SET/RESET voltage(<10%).The increase in the RRAM device length and the application of the optical proximity correction technique can help to reduce the variation to less than 10%,whereas it reduces RRAM read resistance by 4×,resulting in a higher power and area consumption.As such,we provide design guidelines to minimize the electrical variation of RRAM arrays due to the lithography process.展开更多
With the rapid development of machine learning,the demand for high-efficient computing becomes more and more urgent.To break the bottleneck of the traditional Von Neumann architecture,computing-in-memory(CIM)has attra...With the rapid development of machine learning,the demand for high-efficient computing becomes more and more urgent.To break the bottleneck of the traditional Von Neumann architecture,computing-in-memory(CIM)has attracted increasing attention in recent years.In this work,to provide a feasible CIM solution for the large-scale neural networks(NN)requiring continuous weight updating in online training,a flash-based computing-in-memory with high endurance(10^(9) cycles)and ultrafast programming speed is investigated.On the one hand,the proposed programming scheme of channel hot electron injection(CHEI)and hot hole injection(HHI)demonstrate high linearity,symmetric potentiation,and a depression process,which help to improve the training speed and accuracy.On the other hand,the low-damage programming scheme and memory window(MW)optimizations can suppress cell degradation effectively with improved computing accuracy.Even after 109 cycles,the leakage current(I_(off))of cells remains sub-10pA,ensuring the large-scale computing ability of memory.Further characterizations are done on read disturb to demonstrate its robust reliabilities.By processing CIFAR-10 tasks,it is evident that~90%accuracy can be achieved after 109 cycles in both ResNet50 and VGG16 NN.Our results suggest that flash-based CIM has great potential to overcome the limitations of traditional Von Neumann architectures and enable high-performance NN online training,which pave the way for further development of artificial intelligence(AI)accelerators.展开更多
Modern medicine is increasingly interested in advanced sensors to detect and analyze biochemical indicators.Ion sensors based on potentiometric methods are a promising platform for monitoring physiological ions in bio...Modern medicine is increasingly interested in advanced sensors to detect and analyze biochemical indicators.Ion sensors based on potentiometric methods are a promising platform for monitoring physiological ions in biological subjects.Current semi-implantable devices are mainly based on single-parameter detection.Miniaturized semi-implantable electrodes for multiparameter sensing have more restrictions on the electrode size due to biocompatibility considerations,but reducing the electrode surface area could potentially limit electrode sensitivity.This study developed a semi-implantable device system comprising a multiplexed microfilament electrode cluster(MMEC)and a printed circuit board for real-time monitoring of intra-tissue K^(+),Ca^(2+),and Na^(+)concentrations.The electrode surface area was less important for the potentiometric sensing mechanism,suggesting the feasibility of using a tiny fiber-like electrode for potentiometric sensing.The MMEC device exhibited a broad linear response(K^(+):2–32 mmol/L;Ca^(2+):0.5–4 mmol/L;Na^(+):10–160 mmol/L),high sensitivity(about 20–45 mV/decade),temporal stability(>2weeks),and good selectivity(>80%)for the above ions.In vitro detection and in vivo subcutaneous and brain experiment results showed that the MMEC system exhibits good multi-ion monitoring performance in several complex environments.This work provides a platform for the continuous real-time monitoring of ion fluctuations in different situations and has implications for developing smart sensors to monitor human health.展开更多
The single-shot readout data process is essential for the realization of high-fidelity qubits and fault-tolerant quantum algorithms in semiconductor quantum dots. However, the fidelity and visibility of the readout pr...The single-shot readout data process is essential for the realization of high-fidelity qubits and fault-tolerant quantum algorithms in semiconductor quantum dots. However, the fidelity and visibility of the readout process are sensitive to the choice of the thresholds and limited by the experimental hardware. By demonstrating the linear dependence between the measured spin state probabilities and readout visibilities along with dark counts, we describe an alternative threshold-independent method for the single-shot readout of spin qubits in semiconductor quantum dots. We can obtain the extrapolated spin state probabilities of the prepared probabilities of the excited spin state through the threshold-independent method. We then analyze the corresponding errors of the method, finding that errors of the extrapolated probabilities cannot be neglected with no constraints on the readout time and threshold voltage. Therefore, by limiting the readout time and threshold voltage, we ensure the accuracy of the extrapolated probability. We then prove that the efficiency and robustness of this method are 60 times larger than those of the most commonly used method. Moreover, we discuss the influence of the electron temperature on the effective area with a fixed external magnetic field and provide a preliminary demonstration for a single-shot readout of up to 0.7K/1.5T in the future.展开更多
Due to the constraints imposed by physical effects and performance degra certain limitations in sustaining the advancement of Moore’s law.Two-dimensional(2D)materials have emerged as highly promising candidates for t...Due to the constraints imposed by physical effects and performance degra certain limitations in sustaining the advancement of Moore’s law.Two-dimensional(2D)materials have emerged as highly promising candidates for the post-Moore era,offering significant potential in domains such as integrated circuits and next-generation computing.Here,in this review,the progress of 2D semiconductors in process engineering and various electronic applications are summarized.A careful introduction of material synthesis,transistor engineering focused on device configuration,dielectric engineering,contact engineering,and material integration are given first.Then 2D transistors for certain electronic applications including digital and analog circuits,heterogeneous integration chips,and sensing circuits are discussed.Moreover,several promising applications(artificial intelligence chips and quantum chips)based on specific mechanism devices are introduced.Finally,the challenges for 2D materials encountered in achieving circuit-level or system-level applications are analyzed,and potential development pathways or roadmaps are further speculated and outlooked.展开更多
The reverse gate leakage mechanism of W-gate and Ti N-gate AlGaN/GaN high-electron-mobility transistors(HEMTs)with N2plasma surface treatment is investigated using current–voltage(I–V)and capacitance–voltage(C–V)c...The reverse gate leakage mechanism of W-gate and Ti N-gate AlGaN/GaN high-electron-mobility transistors(HEMTs)with N2plasma surface treatment is investigated using current–voltage(I–V)and capacitance–voltage(C–V)characteristics and theoretical calculation analysis.It is found that the main reverse gate leakage mechanism of both devices is the trapassisted tunneling(TAT)mechanism in the entire reverse bias region(-30 V to 0 V).It is also found that the reverse gate leakage current of the W-gate Al GaN/GaN HEMTs is smaller than that of the TiN gate at high reverse gate bias voltage.Moreover,the activation energies of the extracted W-gate and Ti N-gate AlGaN/GaN HEMTs are 0.0551 e V–0.127 eV and0.112 eV–0.201 eV,respectively.展开更多
A power MOSFET with integrated split gate and dummy gate(SD-MOS) is proposed and demonstrated by the TCAD SENTAURUS.The split gate is surrounded by the source and shielded by the dummy gate.Consequently,the coupling a...A power MOSFET with integrated split gate and dummy gate(SD-MOS) is proposed and demonstrated by the TCAD SENTAURUS.The split gate is surrounded by the source and shielded by the dummy gate.Consequently,the coupling area between the split gate and the drain electrode is reduced,thus the gate-to-drain charge(Q_(GD)),reverse transfer capacitance(C_(RSS)) and turn-off loss(E_(off)) are significantly decreased.Moreover,the MOS-channel diode is controlled by the dummy gate with ultra-thin gate oxide t_(ox),which can be turned on before the parasitic P-base/N-drift diode at the reverse conduction,then the majority carriers are injected to the N-drift to attenuate the minority injection.Therefore,the reverse recovery charge(Q_(RR)),time(T_(RR)) and peak current(I_(RRM)) are effectively reduced at the reverse freewheeling state.Additionally,the specific on-resistance(R_(on,sp)) and breakdown voltage(BV) are also studied to evaluate the static properties of the proposed SD-MOS.The simulation results show that the Q_(GD) of 6 nC/cm^(2),the C_(RSS) of 1.1 pF/cm^(2) at the V_(DS) of 150 V,the QRR of 1.2 μC/cm^(2) and the R_(on,sp) of 8.4 mΩ·cm^(2) are obtained,thus the figures of merit(FOM) including Q_(GD) ×R_(on,sp) of50 nC·mΩ,E_(off) × R_(on,sp) of 0.59 mJ·mΩ and the Q_(RR) × R_(on,sp) of 10.1 μC·mΩ are achieved for the proposed SD-MOS.展开更多
A narrowed Si_(0.7)Ge_(0.3)channel fin field-effect transistor(FinFET)device is demonstrated in detail by using an accuratecyclic wet treatment process.The Si_(0.7)Ge_(0.3)fin/per side of 0.63 nm in thickness can be a...A narrowed Si_(0.7)Ge_(0.3)channel fin field-effect transistor(FinFET)device is demonstrated in detail by using an accuratecyclic wet treatment process.The Si_(0.7)Ge_(0.3)fin/per side of 0.63 nm in thickness can be accurately removed in each cycleby utilizing a self-limited oxidation with 40%HNO_(3)solution in 40 s and oxidation removal can be achieved with 1%HFsolution in 10 s.As a result,after the dummy gate removal,the fin width of Si_(0.7)Ge_(0.3)can be narrowed from 20 nm to 8 nmby utilizing 10 cycles of this wet treatment process.Compared with the conventional Si_(0.7)Ge_(0.3)FinFET under a similarprocess,the narrowed Si_(0.7)Ge_(0.3)channel FinFET can realize a strong gate control capability by using this newly developedwet treatment process,because its subthreshold slope can be reduced by 24%,improving from 87 mV/dec to 64 mV/dec.展开更多
This paper demonstrates the importance of three-dimensional(3-D)piezoelectric coupling in the electromechanical behavior of piezoelectric devices using three-dimensional finite element analyses based on weak and stron...This paper demonstrates the importance of three-dimensional(3-D)piezoelectric coupling in the electromechanical behavior of piezoelectric devices using three-dimensional finite element analyses based on weak and strong coupling models for a thin cantilevered piezoelectric bimorph actuator.It is found that there is a significant difference between the strong and weak coupling solutions given by coupling direct and inverse piezoelectric effects(i.e.,piezoelectric coupling effect).In addition,there is significant longitudinal bending caused by the constraint of the inverse piezoelectric effect in the width direction at the fixed end(i.e.,3-D effect).Hence,modeling of these effects or 3-D piezoelectric coupling modeling is an electromechanical basis for the piezoelectric devices,which contributes to the accurate prediction of their behavior.展开更多
Epilepsy is a common neurological disorder that occurs at all ages.Epilepsy not only brings physical pain to patients,but also brings a huge burden to the lives of patients and their families.At present,epilepsy detec...Epilepsy is a common neurological disorder that occurs at all ages.Epilepsy not only brings physical pain to patients,but also brings a huge burden to the lives of patients and their families.At present,epilepsy detection is still achieved through the observation of electroencephalography(EEG)by medical staff.However,this process takes a long time and consumes energy,which will create a huge workload to medical staff.Therefore,it is particularly important to realize the automatic detection of epilepsy.This paper introduces,in detail,the overall framework of EEG-based automatic epilepsy identification and the typical methods involved in each step.Aiming at the core modules,that is,signal acquisition analog front end(AFE),feature extraction and classifier selection,method summary and theoretical explanation are carried out.Finally,the future research directions in the field of automatic detection of epilepsy are prospected.展开更多
Dynamic self-heating effect(SHE)of silicon-on-insulator(SOI)MOSFET is comprehensively evaluated by ultrafast pulsed I-V measurement in this work.It is found for the first time that the SHE complete heating response an...Dynamic self-heating effect(SHE)of silicon-on-insulator(SOI)MOSFET is comprehensively evaluated by ultrafast pulsed I-V measurement in this work.It is found for the first time that the SHE complete heating response and cooling response of SOI MOSFETs are conjugated,with two-stage curves shown.We establish the effective thermal transient response model with stage superposition corresponding to the heating process.The systematic study of SHE dependence on workload shows that frequency and duty cycle have more significant effect on SHE in first-stage heating process than in the second stage.In the first-stage heating process,the peak lattice temperature and current oscillation amplitude decrease by more than 25 K and 4%with frequency increasing to 10 MHz,and when duty cycle is reduced to 25%,the peak lattice temperature drops to 306 K and current oscillation amplitude decreases to 0.77%.Finally,the investigation of two-stage(heating and cooling)process provides a guideline for the unified optimization of dynamic SHE in terms of workload.As the operating frequency is raised to GHz,the peak temperature depends on duty cycle,and self-heating oscillation is completely suppressed.展开更多
We study the charge trapping phenomenon that restricts the endurance of n-type ferroelectric field-effect transistors(FeFETs)with metal/ferroelectric/interlayer/Si(MFIS)gate stack structure.In order to explore the phy...We study the charge trapping phenomenon that restricts the endurance of n-type ferroelectric field-effect transistors(FeFETs)with metal/ferroelectric/interlayer/Si(MFIS)gate stack structure.In order to explore the physical mechanism of the endurance failure caused by the charge trapping effect,we first establish a model to simulate the electron trapping behavior in n-type Si FeFET.The model is based on the quantum mechanical electron tunneling theory.And then,we use the pulsed I_d-V_g method to measure the threshold voltage shift between the rising edges and falling edges of the FeFET.Our model fits the experimental data well.By fitting the model with the experimental data,we get the following conclusions.(i)During the positive operation pulse,electrons in the Si substrate are mainly trapped at the interface between the ferroelectric(FE)layer and interlayer(IL)of the FeFET gate stack by inelastic trap-assisted tunneling.(ii)Based on our model,we can get the number of electrons trapped into the gate stack during the positive operation pulse.(iii)The model can be used to evaluate trap parameters,which will help us to further understand the fatigue mechanism of FeFET.展开更多
As growing applications demand higher driving currents of oxide semiconductor thin-film transistors(TFTs),severe instabilities and even hard breakdown under high-current stress(HCS)become critical challenges.In this w...As growing applications demand higher driving currents of oxide semiconductor thin-film transistors(TFTs),severe instabilities and even hard breakdown under high-current stress(HCS)become critical challenges.In this work,the triggering voltage of HCS-induced self-heating(SH)degradation is defined in the output characteristics of amorphous indium-galliumzinc oxide(a-IGZO)TFTs,and used to quantitatively evaluate the thermal generation process of channel donor defects.The fluorinated a-IGZO(a-IGZO:F)was adopted to effectively retard the triggering of the self-heating(SH)effect,and was supposed to originate from the less population of initial deep-state defects and a slower rate of thermal defect transition in a-IGZO:F.The proposed scheme noticeably enhances the high-current applications of oxide TFTs.展开更多
Heavy ion irradiation effects on charge trapping memory(CTM)capacitors with TiN/Al_(2)O_(3)/HfO_(2)/Al_(2)O_(3)/HfO_(2)/SiO_(2)/p-Si structure have been investigated.The ion-induced interface charges and oxide trap ch...Heavy ion irradiation effects on charge trapping memory(CTM)capacitors with TiN/Al_(2)O_(3)/HfO_(2)/Al_(2)O_(3)/HfO_(2)/SiO_(2)/p-Si structure have been investigated.The ion-induced interface charges and oxide trap charges were calculated and analyzed by capacitance-voltage(C-V)characteristics.The C-V curves shift towards the negative direction after swift heavy ion irradiation,due to the net positive charges accumulating in the trapping layer.The memory window decreases with the increase of ion fluence at high voltage,which results from heavy ion-induced structural damage in the blocking layer.The mechanism of heavy ion irradiation effects on CTM capacitors is discussed in detail with energy band diagrams.The results may help to better understand the physical mechanism of heavy ion-induced degradation of CTM capacitors.展开更多
Al_(1-x)In_(x)N, a Ⅲ-nitride semiconductor material, is currently of great research interest due to its remarkable physical properties and chemical stability. When the Al and In compositions are tuned, its band-gap e...Al_(1-x)In_(x)N, a Ⅲ-nitride semiconductor material, is currently of great research interest due to its remarkable physical properties and chemical stability. When the Al and In compositions are tuned, its band-gap energy varies from 0.7 eV to 6.2 eV, which shows great potential for application in photodetectors. Here, we report the fabrication and performance evaluation of integrated Al_(1-x)In_(x)N on a free-standing GaN substrate through direct radio-frequency magnetron sputtering.The optical properties of Al_(1-x)In_(x)N will be enhanced by the polarization effect of a heterostructure composed of Al_(1-x)In_(x)N and other Ⅲ-nitride materials. An Al_(1-x)In_(x)N/Ga N visible-light photodetector was prepared by semiconductor fabrication technologies such as lithography and metal deposition. The highest photoresponsivity achieved was 1.52 A·W^(-1)under 365 nm wavelength illumination and the photodetector was determined to have the composition Al0.75In0.25N/GaN.A rise time of 0.55 s was observed after transient analysis of the device. The prepared Al_(1-x)In_(x)N visible-light photodetector had a low dark current, high photoresponsivity and fast response speed. By promoting a low-cost, simple fabrication method,this study expands the application of ternary alloy Al_(1-x)In_(x)N visible-light photodetectors in optical communication.展开更多
The effects of ionizing and displacement irradiation of high-energy x-ray and 2-MeV proton on GaN thin films were investigated and compared in this study.The electrical properties of both P-GaN and N-GaN,separated fro...The effects of ionizing and displacement irradiation of high-energy x-ray and 2-MeV proton on GaN thin films were investigated and compared in this study.The electrical properties of both P-GaN and N-GaN,separated from power devices,were gauged for fundamental analysis.It was found that the electrical properties of P-GaN were improved as a consequence of the disruption of the Mg-H bond induced by high-dose x-ray irradiation,as indicated by the Hall and circular transmission line model.Specifically,under a 100-Mrad(Si)x-ray dose,the specific contact resistance pc of P-GaN decreased by 30%,and the hole carrier concentration increased significantly.Additionally,the atom displacement damage effect of a 2-MeV proton of 1×10^(13)p/cm^(2)led to a significant degradation of the electrical properties of P-GaN,while those of N-GaN remained unchanged.P-GaN was found to be more sensitive to irradiation than N-GaN thin film.The effectiveness of x-ray irradiation in enhancing the electrical properties of P-GaN thin films was demonstrated in this study.展开更多
We construct the Hall-bar device with the size of several hundred nanometers based on the HZO/Co multiferroic heterojunction. A remarkable voltage-controlled magnetism is observed in the device that possesses both fer...We construct the Hall-bar device with the size of several hundred nanometers based on the HZO/Co multiferroic heterojunction. A remarkable voltage-controlled magnetism is observed in the device that possesses both ferroelectric property and perpendicular magnetic anisotropy(PMA). The nucleation field and coercivity can be modulated by voltage pulse while saturation field keeps stable. The non-volatile and reversible voltage-controlled magnetism is ascribable to interfacial charges caused by ferroelectric polarization. Meanwhile, the effective anisotropy energy density(Ku) can also be controlled by voltage pulse, a decrease of 83% and increase of 28% in Kuare realized under-3-V and 3-V pulses,respectively. Because the energy barrier is directly proportional to Ku under a given volume, a decreased or enhanced energy barrier can be controlled by voltage pulse. Thus, it is an effective method to realize low-power and high-stability magneto-resistive random-access memory(MRAM).展开更多
A novel metal matrix composites(MMC)with Mg matrix reinforced with natural filler in the form of Didymosphenia geminata frustules(algae with distinctive siliceous shells)are presented in this work.Pulse plasma sinteri...A novel metal matrix composites(MMC)with Mg matrix reinforced with natural filler in the form of Didymosphenia geminata frustules(algae with distinctive siliceous shells)are presented in this work.Pulse plasma sintering(PPS)was used to manufacture Mg-based composites with 1,5 and 10 vol.%ceramic filler.As a reference,pure Mg was sintered.The results show that the addition of 1 vol.%Didymosphenia geminata frustules to the Mg matrix increases its corrosion resistance by supporting passivation reactions,and do not affect the morphology of L929 fibroblasts.Addition of 5 vol.%the filler does not cause cytotoxic effects,but it supports microgalvanic reactions leading to the greater corrosion rate.Higher content than 5 vol.%the filler causes significant microgalvanic corrosion,as well as increases cytotoxicity due to the greater micro-galvanic effect of the composites containing 10 and 15 vol.%diatoms.The results of contact angle measurements show the hydrophilic character of the investigated materials,with slightly increase in numerical values with addition of amount of ceramic reinforcement.The addition of Didymosphenia geminata frustules causes changes in a thermo-elastic properties such as mean apparent value of coefficient of thermal expansion(CTE)and thermal conductivity(λ).The addition of siliceous reinforcement resulted in a linear decrease of CTE and reduction in thermal conductivity over the entire temperature range.With the increasing addition of Didymosphenia geminata frustules,an increase in strength with a decrease in compressive strain is observed.In all composites an increase in microhardness was attained.The results clearly indicate that filler in the form of Didymosphenia geminata frustules may significantly change the most important properties of pure Mg,indicating its wide potential in the application of Mg-based composites with a special focus on biomedical use.展开更多
In this work,a novel one-time-programmable memory unit based on a Schottky-type p-GaN diode is proposed.During the programming process,the junction switches from a high-resistance state to a low-resistance state throu...In this work,a novel one-time-programmable memory unit based on a Schottky-type p-GaN diode is proposed.During the programming process,the junction switches from a high-resistance state to a low-resistance state through Schottky junction breakdown,and the state is permanently preserved.The memory unit features a current ratio of more than 10^(3),a read voltage window of 6 V,a programming time of less than 10^(−4)s,a stability of more than 108 read cycles,and a lifetime of far more than 10 years.Besides,the fabrication of the device is fully compatible with commercial Si-based GaN process platforms,which is of great significance for the realization of low-cost read-only memory in all-GaN integration.展开更多
Switched-capacitor(SC)DC-DC converter[1]is an impor-tant alternative to inductive DC-DC converter,in terms of removing the bulky power inductor.Hence,it is widely used in low-profile,low-power applications,such as the...Switched-capacitor(SC)DC-DC converter[1]is an impor-tant alternative to inductive DC-DC converter,in terms of removing the bulky power inductor.Hence,it is widely used in low-profile,low-power applications,such as the internet of things(IoT)sensor nodes and energy harvesting[2].Mean-while,considering that capacitor has a much higher energy density than inductor,high-power applications.展开更多
基金supported in part by the Open Fund of State Key Laboratory of Integrated Chips and Systems,Fudan Universityin part by the National Science Foundation of China under Grant No.62304133 and No.62350610271.
文摘Reducing the process variation is a significant concern for resistive random access memory(RRAM).Due to its ultrahigh integration density,RRAM arrays are prone to lithographic variation during the lithography process,introducing electrical variation among different RRAM devices.In this work,an optical physical verification methodology for the RRAM array is developed,and the effects of different layout parameters on important electrical characteristics are systematically investigated.The results indicate that the RRAM devices can be categorized into three clusters according to their locations and lithography environments.The read resistance is more sensitive to the locations in the array(~30%)than SET/RESET voltage(<10%).The increase in the RRAM device length and the application of the optical proximity correction technique can help to reduce the variation to less than 10%,whereas it reduces RRAM read resistance by 4×,resulting in a higher power and area consumption.As such,we provide design guidelines to minimize the electrical variation of RRAM arrays due to the lithography process.
基金This work was supported by the National Natural Science Foundation of China(Nos.62034006,92264201,and 91964105)the Natural Science Foundation of Shandong Province(Nos.ZR2020JQ28 and ZR2020KF016)the Program of Qilu Young Scholars of Shandong University.
文摘With the rapid development of machine learning,the demand for high-efficient computing becomes more and more urgent.To break the bottleneck of the traditional Von Neumann architecture,computing-in-memory(CIM)has attracted increasing attention in recent years.In this work,to provide a feasible CIM solution for the large-scale neural networks(NN)requiring continuous weight updating in online training,a flash-based computing-in-memory with high endurance(10^(9) cycles)and ultrafast programming speed is investigated.On the one hand,the proposed programming scheme of channel hot electron injection(CHEI)and hot hole injection(HHI)demonstrate high linearity,symmetric potentiation,and a depression process,which help to improve the training speed and accuracy.On the other hand,the low-damage programming scheme and memory window(MW)optimizations can suppress cell degradation effectively with improved computing accuracy.Even after 109 cycles,the leakage current(I_(off))of cells remains sub-10pA,ensuring the large-scale computing ability of memory.Further characterizations are done on read disturb to demonstrate its robust reliabilities.By processing CIFAR-10 tasks,it is evident that~90%accuracy can be achieved after 109 cycles in both ResNet50 and VGG16 NN.Our results suggest that flash-based CIM has great potential to overcome the limitations of traditional Von Neumann architectures and enable high-performance NN online training,which pave the way for further development of artificial intelligence(AI)accelerators.
基金The authors would like to acknowledge financial support from the National Key R&D Program of China(Nos.2021YFF1200700 and 2021YFA0911100)the National Natural Science Foundation of China(Nos.T2225010,32171399,and 32171456)+4 种基金the Fundamental Research Funds for the Central Universities,Sun Yat-Sen University(No.22dfx02)Pazhou Lab,Guangzhou(No.PZL2021KF0003)The authors also would like to thank the funding support from the Opening Project of Key Laboratory of Microelectronic Devices&Integrated Technology,Institute of Microelectronics,Chinese Academy of Sciences,and State Key Laboratory of Precision Measuring Technology and Instruments(No.pilab2211)QQOY would like to thank the China Postdoctoral Science Foundation(No.2022M713645)JL would like to thank the National Natural Science Foundation of China(No.62105380)and the China Postdoctoral Science Foundation(No.2021M693686).
文摘Modern medicine is increasingly interested in advanced sensors to detect and analyze biochemical indicators.Ion sensors based on potentiometric methods are a promising platform for monitoring physiological ions in biological subjects.Current semi-implantable devices are mainly based on single-parameter detection.Miniaturized semi-implantable electrodes for multiparameter sensing have more restrictions on the electrode size due to biocompatibility considerations,but reducing the electrode surface area could potentially limit electrode sensitivity.This study developed a semi-implantable device system comprising a multiplexed microfilament electrode cluster(MMEC)and a printed circuit board for real-time monitoring of intra-tissue K^(+),Ca^(2+),and Na^(+)concentrations.The electrode surface area was less important for the potentiometric sensing mechanism,suggesting the feasibility of using a tiny fiber-like electrode for potentiometric sensing.The MMEC device exhibited a broad linear response(K^(+):2–32 mmol/L;Ca^(2+):0.5–4 mmol/L;Na^(+):10–160 mmol/L),high sensitivity(about 20–45 mV/decade),temporal stability(>2weeks),and good selectivity(>80%)for the above ions.In vitro detection and in vivo subcutaneous and brain experiment results showed that the MMEC system exhibits good multi-ion monitoring performance in several complex environments.This work provides a platform for the continuous real-time monitoring of ion fluctuations in different situations and has implications for developing smart sensors to monitor human health.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.12074368,92165207,12034018,and 62004185)the Anhui Province Natural Science Foundation (Grant No.2108085J03)the USTC Tang Scholarship。
文摘The single-shot readout data process is essential for the realization of high-fidelity qubits and fault-tolerant quantum algorithms in semiconductor quantum dots. However, the fidelity and visibility of the readout process are sensitive to the choice of the thresholds and limited by the experimental hardware. By demonstrating the linear dependence between the measured spin state probabilities and readout visibilities along with dark counts, we describe an alternative threshold-independent method for the single-shot readout of spin qubits in semiconductor quantum dots. We can obtain the extrapolated spin state probabilities of the prepared probabilities of the excited spin state through the threshold-independent method. We then analyze the corresponding errors of the method, finding that errors of the extrapolated probabilities cannot be neglected with no constraints on the readout time and threshold voltage. Therefore, by limiting the readout time and threshold voltage, we ensure the accuracy of the extrapolated probability. We then prove that the efficiency and robustness of this method are 60 times larger than those of the most commonly used method. Moreover, we discuss the influence of the electron temperature on the effective area with a fixed external magnetic field and provide a preliminary demonstration for a single-shot readout of up to 0.7K/1.5T in the future.
基金supported in part by STI 2030-Major Projects under Grant 2022ZD0209200sponsored by Tsinghua-Toyota Joint Research Fund+12 种基金in part by National Natural Science Foundation of China under Grant 62374099, Grant 62022047, Grant U20A20168, Grant 51861145202, Grant 51821003, and Grant 62175219in part by the National Key R&D Program under Grant 2016YFA0200400in part by Beijing Natural Science-Xiaomi Innovation Joint Fund Grant L233009in part supported by Tsinghua University-Zhuhai Huafa Industrial Share Company Joint Institute for Architecture Optoelectronic Technologies (JIAOT KF202204)in part by the Daikin-Tsinghua Union Programin part sponsored by CIE-Tencent Robotics X Rhino-Bird Focused Research Programin part by the Guoqiang Institute, Tsinghua Universityin part by the Research Fund from Beijing Innovation Center for Future Chipin part by Shanxi “1331 Project” Key Subjects Constructionin part by the Youth Innovation Promotion Association of Chinese Academy of Sciences (2019120)the opening fund of Key Laboratory of Science and Technology on Silicon Devices, Chinese Academy of Sciencesin part by the project of MOE Innovation Platformin part by the State Key Laboratory of Integrated Chips and Systems
文摘Due to the constraints imposed by physical effects and performance degra certain limitations in sustaining the advancement of Moore’s law.Two-dimensional(2D)materials have emerged as highly promising candidates for the post-Moore era,offering significant potential in domains such as integrated circuits and next-generation computing.Here,in this review,the progress of 2D semiconductors in process engineering and various electronic applications are summarized.A careful introduction of material synthesis,transistor engineering focused on device configuration,dielectric engineering,contact engineering,and material integration are given first.Then 2D transistors for certain electronic applications including digital and analog circuits,heterogeneous integration chips,and sensing circuits are discussed.Moreover,several promising applications(artificial intelligence chips and quantum chips)based on specific mechanism devices are introduced.Finally,the challenges for 2D materials encountered in achieving circuit-level or system-level applications are analyzed,and potential development pathways or roadmaps are further speculated and outlooked.
文摘The reverse gate leakage mechanism of W-gate and Ti N-gate AlGaN/GaN high-electron-mobility transistors(HEMTs)with N2plasma surface treatment is investigated using current–voltage(I–V)and capacitance–voltage(C–V)characteristics and theoretical calculation analysis.It is found that the main reverse gate leakage mechanism of both devices is the trapassisted tunneling(TAT)mechanism in the entire reverse bias region(-30 V to 0 V).It is also found that the reverse gate leakage current of the W-gate Al GaN/GaN HEMTs is smaller than that of the TiN gate at high reverse gate bias voltage.Moreover,the activation energies of the extracted W-gate and Ti N-gate AlGaN/GaN HEMTs are 0.0551 e V–0.127 eV and0.112 eV–0.201 eV,respectively.
基金Project supported by the National Natural Science Foundation of China (Grants No. 61604027 and 61704016)the Chongqing Natural Science Foundation, China (Grant No. cstc2020jcyj-msxmX0550)。
文摘A power MOSFET with integrated split gate and dummy gate(SD-MOS) is proposed and demonstrated by the TCAD SENTAURUS.The split gate is surrounded by the source and shielded by the dummy gate.Consequently,the coupling area between the split gate and the drain electrode is reduced,thus the gate-to-drain charge(Q_(GD)),reverse transfer capacitance(C_(RSS)) and turn-off loss(E_(off)) are significantly decreased.Moreover,the MOS-channel diode is controlled by the dummy gate with ultra-thin gate oxide t_(ox),which can be turned on before the parasitic P-base/N-drift diode at the reverse conduction,then the majority carriers are injected to the N-drift to attenuate the minority injection.Therefore,the reverse recovery charge(Q_(RR)),time(T_(RR)) and peak current(I_(RRM)) are effectively reduced at the reverse freewheeling state.Additionally,the specific on-resistance(R_(on,sp)) and breakdown voltage(BV) are also studied to evaluate the static properties of the proposed SD-MOS.The simulation results show that the Q_(GD) of 6 nC/cm^(2),the C_(RSS) of 1.1 pF/cm^(2) at the V_(DS) of 150 V,the QRR of 1.2 μC/cm^(2) and the R_(on,sp) of 8.4 mΩ·cm^(2) are obtained,thus the figures of merit(FOM) including Q_(GD) ×R_(on,sp) of50 nC·mΩ,E_(off) × R_(on,sp) of 0.59 mJ·mΩ and the Q_(RR) × R_(on,sp) of 10.1 μC·mΩ are achieved for the proposed SD-MOS.
基金Project supported by the Beijing Municipal Natural Science Foundation,China(Grant No.4202078).
文摘A narrowed Si_(0.7)Ge_(0.3)channel fin field-effect transistor(FinFET)device is demonstrated in detail by using an accuratecyclic wet treatment process.The Si_(0.7)Ge_(0.3)fin/per side of 0.63 nm in thickness can be accurately removed in each cycleby utilizing a self-limited oxidation with 40%HNO_(3)solution in 40 s and oxidation removal can be achieved with 1%HFsolution in 10 s.As a result,after the dummy gate removal,the fin width of Si_(0.7)Ge_(0.3)can be narrowed from 20 nm to 8 nmby utilizing 10 cycles of this wet treatment process.Compared with the conventional Si_(0.7)Ge_(0.3)FinFET under a similarprocess,the narrowed Si_(0.7)Ge_(0.3)channel FinFET can realize a strong gate control capability by using this newly developedwet treatment process,because its subthreshold slope can be reduced by 24%,improving from 87 mV/dec to 64 mV/dec.
基金supported by the Japan Society for the Promotion of Science under KAKENHI Grant Nos.19F19379 and 20H04199。
文摘This paper demonstrates the importance of three-dimensional(3-D)piezoelectric coupling in the electromechanical behavior of piezoelectric devices using three-dimensional finite element analyses based on weak and strong coupling models for a thin cantilevered piezoelectric bimorph actuator.It is found that there is a significant difference between the strong and weak coupling solutions given by coupling direct and inverse piezoelectric effects(i.e.,piezoelectric coupling effect).In addition,there is significant longitudinal bending caused by the constraint of the inverse piezoelectric effect in the width direction at the fixed end(i.e.,3-D effect).Hence,modeling of these effects or 3-D piezoelectric coupling modeling is an electromechanical basis for the piezoelectric devices,which contributes to the accurate prediction of their behavior.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences,Grant No.XDA0330000 and Grant No.XDB44000000。
文摘Epilepsy is a common neurological disorder that occurs at all ages.Epilepsy not only brings physical pain to patients,but also brings a huge burden to the lives of patients and their families.At present,epilepsy detection is still achieved through the observation of electroencephalography(EEG)by medical staff.However,this process takes a long time and consumes energy,which will create a huge workload to medical staff.Therefore,it is particularly important to realize the automatic detection of epilepsy.This paper introduces,in detail,the overall framework of EEG-based automatic epilepsy identification and the typical methods involved in each step.Aiming at the core modules,that is,signal acquisition analog front end(AFE),feature extraction and classifier selection,method summary and theoretical explanation are carried out.Finally,the future research directions in the field of automatic detection of epilepsy are prospected.
文摘Dynamic self-heating effect(SHE)of silicon-on-insulator(SOI)MOSFET is comprehensively evaluated by ultrafast pulsed I-V measurement in this work.It is found for the first time that the SHE complete heating response and cooling response of SOI MOSFETs are conjugated,with two-stage curves shown.We establish the effective thermal transient response model with stage superposition corresponding to the heating process.The systematic study of SHE dependence on workload shows that frequency and duty cycle have more significant effect on SHE in first-stage heating process than in the second stage.In the first-stage heating process,the peak lattice temperature and current oscillation amplitude decrease by more than 25 K and 4%with frequency increasing to 10 MHz,and when duty cycle is reduced to 25%,the peak lattice temperature drops to 306 K and current oscillation amplitude decreases to 0.77%.Finally,the investigation of two-stage(heating and cooling)process provides a guideline for the unified optimization of dynamic SHE in terms of workload.As the operating frequency is raised to GHz,the peak temperature depends on duty cycle,and self-heating oscillation is completely suppressed.
基金Project supported by the National Natural Science Foundation of China(Grant No.92264104)。
文摘We study the charge trapping phenomenon that restricts the endurance of n-type ferroelectric field-effect transistors(FeFETs)with metal/ferroelectric/interlayer/Si(MFIS)gate stack structure.In order to explore the physical mechanism of the endurance failure caused by the charge trapping effect,we first establish a model to simulate the electron trapping behavior in n-type Si FeFET.The model is based on the quantum mechanical electron tunneling theory.And then,we use the pulsed I_d-V_g method to measure the threshold voltage shift between the rising edges and falling edges of the FeFET.Our model fits the experimental data well.By fitting the model with the experimental data,we get the following conclusions.(i)During the positive operation pulse,electrons in the Si substrate are mainly trapped at the interface between the ferroelectric(FE)layer and interlayer(IL)of the FeFET gate stack by inelastic trap-assisted tunneling.(ii)Based on our model,we can get the number of electrons trapped into the gate stack during the positive operation pulse.(iii)The model can be used to evaluate trap parameters,which will help us to further understand the fatigue mechanism of FeFET.
基金supported by National Key Research and Development Program under Grant No.2022YFB3607100Shenzhen Research Programs under Grant Nos.JCYJ20200109140601691,JCYJ20190808154803565,SGDX20201103095607022,SGDX20211123145404006,and GXWD20201231165807007-20200807025846001。
文摘As growing applications demand higher driving currents of oxide semiconductor thin-film transistors(TFTs),severe instabilities and even hard breakdown under high-current stress(HCS)become critical challenges.In this work,the triggering voltage of HCS-induced self-heating(SH)degradation is defined in the output characteristics of amorphous indium-galliumzinc oxide(a-IGZO)TFTs,and used to quantitatively evaluate the thermal generation process of channel donor defects.The fluorinated a-IGZO(a-IGZO:F)was adopted to effectively retard the triggering of the self-heating(SH)effect,and was supposed to originate from the less population of initial deep-state defects and a slower rate of thermal defect transition in a-IGZO:F.The proposed scheme noticeably enhances the high-current applications of oxide TFTs.
基金the National Natural Science Foundation of China(Grant Nos.12105340,12035019,and12075290)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2020412)。
文摘Heavy ion irradiation effects on charge trapping memory(CTM)capacitors with TiN/Al_(2)O_(3)/HfO_(2)/Al_(2)O_(3)/HfO_(2)/SiO_(2)/p-Si structure have been investigated.The ion-induced interface charges and oxide trap charges were calculated and analyzed by capacitance-voltage(C-V)characteristics.The C-V curves shift towards the negative direction after swift heavy ion irradiation,due to the net positive charges accumulating in the trapping layer.The memory window decreases with the increase of ion fluence at high voltage,which results from heavy ion-induced structural damage in the blocking layer.The mechanism of heavy ion irradiation effects on CTM capacitors is discussed in detail with energy band diagrams.The results may help to better understand the physical mechanism of heavy ion-induced degradation of CTM capacitors.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61974144, 62004127, and 12074263)Key-Area Research and Development Program of Guangdong Province (Grant Nos. 2020B010174003 and 2020B010169001)+2 种基金Guangdong Science Foundation for Distinguished Young Scholars (Grant No. 2022B1515020073)the Science and Technology Foundation of Shenzhen (Grant No. JSGG20191129114216474)the Open Project of State Key Laboratory of Functional Materials for Informatics。
文摘Al_(1-x)In_(x)N, a Ⅲ-nitride semiconductor material, is currently of great research interest due to its remarkable physical properties and chemical stability. When the Al and In compositions are tuned, its band-gap energy varies from 0.7 eV to 6.2 eV, which shows great potential for application in photodetectors. Here, we report the fabrication and performance evaluation of integrated Al_(1-x)In_(x)N on a free-standing GaN substrate through direct radio-frequency magnetron sputtering.The optical properties of Al_(1-x)In_(x)N will be enhanced by the polarization effect of a heterostructure composed of Al_(1-x)In_(x)N and other Ⅲ-nitride materials. An Al_(1-x)In_(x)N/Ga N visible-light photodetector was prepared by semiconductor fabrication technologies such as lithography and metal deposition. The highest photoresponsivity achieved was 1.52 A·W^(-1)under 365 nm wavelength illumination and the photodetector was determined to have the composition Al0.75In0.25N/GaN.A rise time of 0.55 s was observed after transient analysis of the device. The prepared Al_(1-x)In_(x)N visible-light photodetector had a low dark current, high photoresponsivity and fast response speed. By promoting a low-cost, simple fabrication method,this study expands the application of ternary alloy Al_(1-x)In_(x)N visible-light photodetectors in optical communication.
文摘The effects of ionizing and displacement irradiation of high-energy x-ray and 2-MeV proton on GaN thin films were investigated and compared in this study.The electrical properties of both P-GaN and N-GaN,separated from power devices,were gauged for fundamental analysis.It was found that the electrical properties of P-GaN were improved as a consequence of the disruption of the Mg-H bond induced by high-dose x-ray irradiation,as indicated by the Hall and circular transmission line model.Specifically,under a 100-Mrad(Si)x-ray dose,the specific contact resistance pc of P-GaN decreased by 30%,and the hole carrier concentration increased significantly.Additionally,the atom displacement damage effect of a 2-MeV proton of 1×10^(13)p/cm^(2)led to a significant degradation of the electrical properties of P-GaN,while those of N-GaN remained unchanged.P-GaN was found to be more sensitive to irradiation than N-GaN thin film.The effectiveness of x-ray irradiation in enhancing the electrical properties of P-GaN thin films was demonstrated in this study.
基金supported by Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA18000000)the Fund from the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No. 2015097)Guangzhou City Research and Development Program in Key Fields (Grant No. 202103020001)。
文摘We construct the Hall-bar device with the size of several hundred nanometers based on the HZO/Co multiferroic heterojunction. A remarkable voltage-controlled magnetism is observed in the device that possesses both ferroelectric property and perpendicular magnetic anisotropy(PMA). The nucleation field and coercivity can be modulated by voltage pulse while saturation field keeps stable. The non-volatile and reversible voltage-controlled magnetism is ascribable to interfacial charges caused by ferroelectric polarization. Meanwhile, the effective anisotropy energy density(Ku) can also be controlled by voltage pulse, a decrease of 83% and increase of 28% in Kuare realized under-3-V and 3-V pulses,respectively. Because the energy barrier is directly proportional to Ku under a given volume, a decreased or enhanced energy barrier can be controlled by voltage pulse. Thus, it is an effective method to realize low-power and high-stability magneto-resistive random-access memory(MRAM).
基金Izabela B.Zgłobicka acknowledges the funding provided by National Science Center for providing financial support to project Metal Matrix Composites with natural filler(Grant No.2018/31/D/ST8/00890).The authors are grateful to Dr Matt P.Ashworth from the University of Texas at Austin(USA)for critically reading the manuscript and correcting the language.
文摘A novel metal matrix composites(MMC)with Mg matrix reinforced with natural filler in the form of Didymosphenia geminata frustules(algae with distinctive siliceous shells)are presented in this work.Pulse plasma sintering(PPS)was used to manufacture Mg-based composites with 1,5 and 10 vol.%ceramic filler.As a reference,pure Mg was sintered.The results show that the addition of 1 vol.%Didymosphenia geminata frustules to the Mg matrix increases its corrosion resistance by supporting passivation reactions,and do not affect the morphology of L929 fibroblasts.Addition of 5 vol.%the filler does not cause cytotoxic effects,but it supports microgalvanic reactions leading to the greater corrosion rate.Higher content than 5 vol.%the filler causes significant microgalvanic corrosion,as well as increases cytotoxicity due to the greater micro-galvanic effect of the composites containing 10 and 15 vol.%diatoms.The results of contact angle measurements show the hydrophilic character of the investigated materials,with slightly increase in numerical values with addition of amount of ceramic reinforcement.The addition of Didymosphenia geminata frustules causes changes in a thermo-elastic properties such as mean apparent value of coefficient of thermal expansion(CTE)and thermal conductivity(λ).The addition of siliceous reinforcement resulted in a linear decrease of CTE and reduction in thermal conductivity over the entire temperature range.With the increasing addition of Didymosphenia geminata frustules,an increase in strength with a decrease in compressive strain is observed.In all composites an increase in microhardness was attained.The results clearly indicate that filler in the form of Didymosphenia geminata frustules may significantly change the most important properties of pure Mg,indicating its wide potential in the application of Mg-based composites with a special focus on biomedical use.
基金supported in part by the National Key Research and Development Program of China under Grant 2022YFB3604400in part by the Youth Innovation Promotion Association of Chinese Academy Sciences (CAS)+4 种基金in part by the CAS-Croucher Funding Scheme under Grant CAS22801in part by National Natural Science Foundation of China under Grant 62334012, Grant 62074161, Grant 62004213, Grant U20A20208, and Grant 62304252in part by the Beijing Municipal Science and Technology Commission project under Grant Z201100008420009 and Grant Z211100007921018in part by the University of CASin part by the IMECAS-HKUST-Joint Laboratory of Microelectronics
文摘In this work,a novel one-time-programmable memory unit based on a Schottky-type p-GaN diode is proposed.During the programming process,the junction switches from a high-resistance state to a low-resistance state through Schottky junction breakdown,and the state is permanently preserved.The memory unit features a current ratio of more than 10^(3),a read voltage window of 6 V,a programming time of less than 10^(−4)s,a stability of more than 108 read cycles,and a lifetime of far more than 10 years.Besides,the fabrication of the device is fully compatible with commercial Si-based GaN process platforms,which is of great significance for the realization of low-cost read-only memory in all-GaN integration.
基金This work is supported by the Macao Science and Technology Development Fund(FDCT)under Grant 0041/2022/A1by the Research Committee of University of Macao under Grant MYRG2022-00004-IME.
文摘Switched-capacitor(SC)DC-DC converter[1]is an impor-tant alternative to inductive DC-DC converter,in terms of removing the bulky power inductor.Hence,it is widely used in low-profile,low-power applications,such as the internet of things(IoT)sensor nodes and energy harvesting[2].Mean-while,considering that capacitor has a much higher energy density than inductor,high-power applications.
