We report a back-gated metal-oxide-ferroelectric-metal (MOFM) field-effect transistor (FET) with lead zirconate titanate (PZT) material, in which an Al doped zinc oxide (AZO) channel layer with an optimized do...We report a back-gated metal-oxide-ferroelectric-metal (MOFM) field-effect transistor (FET) with lead zirconate titanate (PZT) material, in which an Al doped zinc oxide (AZO) channel layer with an optimized doping concentration of 1% is applied to reduce the channel resistance of the channel layer, thus guaranteeing a large enough load capacity of the transistor. The hysteresis loops of the Pt/PZT/AZO/Ti/Pt capacitor are measured and compared with a Pt/PZT/Pt capacitor, indicating that the remnant polarization is almost 40 μC/cm^2 and the polarization is saturated at 20 V. The measured capacitance-voltage properties are analyzed as a result of the electron depletion and accumulation switching operation conducted by the modulation of PZT on AZO channel resistance caused by the switchable remnant polarization of PZT. The switching properties of the AZO channel layer are also proved by the current-voltage transfer curves measured in the back-gated MOFM ferroelectric FET, which also show a drain current switching ratio up to about 100 times.展开更多
Organic ferroelectric field-effect transistors (OFeFETs) are regarded as a promising technology for low-cost flexible memories. However, the electrical instability is still a critical obstacle, which limits the comm...Organic ferroelectric field-effect transistors (OFeFETs) are regarded as a promising technology for low-cost flexible memories. However, the electrical instability is still a critical obstacle, which limits the commercialization process. Based on already established models for polarization in ferroelectrics and charge transport in OFeFETs, simulation work is performed to determine the influence of polarization fatigue and ferroelectric switching transient on electrical characteristics in OFeFETs. The polarization fatigue results in the decrease of the on-state drain current and the memory window width and thus degrades the memory performance. The output measurements during the ferroelectric switching process show a hysteresis due to the instable polarization. In the on/off measurements, a large writing/erasing pulse frequency weakens the polarization modulation and thus results in a small separation between on- and off-state drain currents. According to the electrical properties of the ferroelectric layer, suggestions are given to obtain optimal electrical characterization for OFeFETs.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
Integrating ferroelectric negative capacitance(NC)into the field-effect transistor(FET)promises to break fundamental limits of power dissipation known as Boltzmann tyranny.However,realizing the stable static negative ...Integrating ferroelectric negative capacitance(NC)into the field-effect transistor(FET)promises to break fundamental limits of power dissipation known as Boltzmann tyranny.However,realizing the stable static negative capacitance in the non-transient non-hysteretic regime remains a daunting task.The problem stems from the lack of understanding of how the fundamental origin of the NC due to the emergence of the domain state can be put in use for implementing the NC FET.Here we put forth an ingenious design for the ferroelectric domain-based field-effect transistor with the stable reversible static negative capacitance.Using dielectric coating of the ferroelectric capacitor enables the tunability of the negative capacitance improving tremendously the performance of the field-effect transistors.展开更多
Multilevel ferroelectric field-effect transistors(FeFETs)integrated with HfO_(2)-based ferroelectric thin films demonstrate tremendous potential in high-speed massive data storage and neuromorphic computing applicatio...Multilevel ferroelectric field-effect transistors(FeFETs)integrated with HfO_(2)-based ferroelectric thin films demonstrate tremendous potential in high-speed massive data storage and neuromorphic computing applications.However,few works have focused on the stability of the multiple memory states in the HfO_(2)-based FeFETs.Here we firstly report the write/read disturb effects on the multiple memory states in the Hf_(0.5)Zr_(0.5)O_(2)(HZO)-based FeFETs.The multiple memory states in HZO-based FeFETs do not show obvious degradation with the write and read disturb cycles.Moreover,the retention characteristics of the intermediate memory states in HZO-based FeFETs with unsaturated ferroelectric polarizations are better than that of the memory state with saturated ferroelectric polarization.Through the deep analysis of the operation principle of in HZO-based FeFETs,we speculate that the better retention properties of intermediate memory states are determined by the less ferroelectric polarization degradation and the weaker ferroelectric polarization shielding.The experimental and theoretical evidences confirm that the long-term stability of the intermediate memory states in HZO-based FeFETs are as robust as that of the saturated memory state,laying a solid foundation for their practical applications.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
The instability of plasma waves in the channel of field-effect transistors will cause the electromagnetic waves with THz frequency.Based on a self-consistent quantum hydrodynamic model,the instability of THz plasmas w...The instability of plasma waves in the channel of field-effect transistors will cause the electromagnetic waves with THz frequency.Based on a self-consistent quantum hydrodynamic model,the instability of THz plasmas waves in the channel of graphene field-effect transistors has been investigated with external magnetic field and quantum effects.We analyzed the influence of weak magnetic fields,quantum effects,device size,and temperature on the instability of plasma waves under asymmetric boundary conditions numerically.The results show that the magnetic fields,quantum effects,and the thickness of the dielectric layer between the gate and the channel can increase the radiation frequency.Additionally,we observed that increase in temperature leads to a decrease in both oscillation frequency and instability increment.The numerical results and accompanying images obtained from our simulations provide support for the above conclusions.展开更多
A facile approach was demonstrated for fabricating high-performance nonvolatile memory devices based on ferroelectric-gate field effect transistors using a p-type Si nanowire coated with omega-shaped gate organic ferr...A facile approach was demonstrated for fabricating high-performance nonvolatile memory devices based on ferroelectric-gate field effect transistors using a p-type Si nanowire coated with omega-shaped gate organic ferroelectric poly(vinylidene fluoride-trifluoroethylene)(P(VDF-Tr FE)). We overcame the interfacial layer problem by incorporating P(VDF-Tr FE) as a ferroelectric gate using a low-temperature fabrication process. Our memory devices exhibited excellent memory characteristics with a low programming voltage of ±5 V, a large modulation in channel conductance between ON and OFF states exceeding 105, a long retention time greater than 3 9 104 s, and a high endurance of over 105 programming cycles while maintaining an ION/IOFFratio higher than 102.展开更多
The integration between infrared detection and modern microelectronics offers unique opportunities for compact and high-resolution infrared imaging.However,silicon,the cornerstone of modern microelectronics,can only d...The integration between infrared detection and modern microelectronics offers unique opportunities for compact and high-resolution infrared imaging.However,silicon,the cornerstone of modern microelectronics,can only detect light within a limited wavelength range(<1100 nm)due to its bandgap of 1.12 eV,which restricts its utility in the infrared detection realm.Herein,a photo-driven fin field-effect transistor is presented,which breaks the spectral response constraint of conventional silicon detectors while achieving sensitive infrared detection.This device comprises a fin-shaped silicon channel for charge transport and a lead sulfide film for infrared light harvesting.The lead sulfide film wraps the silicon channel to form a“three-dimensional”infrared-sensitive gate,enabling the photovoltage generated at the lead sulfide-silicon junction to effectively modulate the channel conductance.At room temperature,this device realizes a broadband photodetection from visible(635 nm)to short-wave infrared regions(2700 nm),surpassing the working range of the regular indium gallium arsenide and germanium detectors.Furthermore,it exhibits low equivalent noise powers of 3.2×10^(-12) W·Hz^(-1/2) and 2.3×10^(-11) W·Hz^(-1/2) under 1550 nm and 2700 nm illumination,respectively.These results highlight the significant potential of photo-driven fin field-effect transistors in advancing uncooled silicon-based infrared detection.展开更多
Organic ferroelectric memory devices based on field effect transistors that can be configured between two stable states of on and off have been widely researched as the next generation data storage media in recent yea...Organic ferroelectric memory devices based on field effect transistors that can be configured between two stable states of on and off have been widely researched as the next generation data storage media in recent years.This emerging type of memory devices can lead to a new instrument system as a potential alternative to previous non-volatile memory building blocks in future processing units because of their numerous merits such as cost-effective process,simple structure and freedom in substrate choices.This bi-stable non-volatile memory device of information storage has been investigated using several organic or inorganic semiconductors with organic ferroelectric polymer materials.Recent progresses in this ferroelectric memory field,hybrid system have attracted a lot of attention due to their excellent device performance in comparison with that of all organic systems.In this paper,a general review of this type of ferroelectric non-volatile memory is provided,which include the device structure,organic ferroelectric materials,electrical characteristics and working principles.We also present some snapshots of our previous study on hybrid ferroelectric memories including our recent work based on zinc oxide nanowire channels.展开更多
Flexible electronics are transforming our lives by making daily activities more convenient.Central to this innovation are field-effect transistors(FETs),valued for their efficient signal processing,nanoscale fabricati...Flexible electronics are transforming our lives by making daily activities more convenient.Central to this innovation are field-effect transistors(FETs),valued for their efficient signal processing,nanoscale fabrication,low-power consumption,fast response times,and versatility.Graphene,known for its exceptional mechanical properties,high electron mobility,and biocompatibility,is an ideal material for FET channels and sensors.The combination of graphene and FETs has given rise to flexible graphene field-effect transistors(FGFETs),driving significant advances in flexible electronics and sparked a strong interest in flexible biomedical sensors.Here,we first provide a brief overview of the basic structure,operating mechanism,and evaluation parameters of FGFETs,and delve into their material selection and patterning techniques.The ability of FGFETs to sense strains and biomolecular charges opens up diverse application possibilities.We specifically analyze the latest strategies for integrating FGFETs into wearable and implantable flexible biomedical sensors,focusing on the key aspects of constructing high-quality flexible biomedical sensors.Finally,we discuss the current challenges and prospects of FGFETs and their applications in biomedical sensors.This review will provide valuable insights and inspiration for ongoing research to improve the quality of FGFETs and broaden their application prospects in flexible biomedical sensing.展开更多
This paper describes the foundation underlying the device physics and theory of the semiconductor field effect transistor which is applicable to any devices with two carrier species in an electric field. The importanc...This paper describes the foundation underlying the device physics and theory of the semiconductor field effect transistor which is applicable to any devices with two carrier species in an electric field. The importance of the boundary conditions on the device current-voltage characteristics is discussed. An illustration is given of the transfer DCIV characteristics computed for two boundary conditions,one on electrical potential,giving much higher drift-limited parabolic current through the intrinsic transistor, and the other on the electrochemical potentials, giving much lower injection-over-thebarrier diffusion-limited current with ideal 60mV per decade exponential subthreshold roll-off, simulating electron and hole contacts. The two-MOS-gates on thin pure-body silicon field-effect transistor is used as examples展开更多
This paper describes the bipolar field-effect transistor (BiFET) and its theory. Analytical solution is ob- tained from partitioning the two-dimensional transistor into two one-dimensional transistors. The analysis ...This paper describes the bipolar field-effect transistor (BiFET) and its theory. Analytical solution is ob- tained from partitioning the two-dimensional transistor into two one-dimensional transistors. The analysis employs the parametric surface-electric-potential and the electrochemical (quasi-Fermi) potential-gradient driving force to compute the current. Output and transfer D. C. current and conductance versus voltage are presented over practi- cal ranges of terminal D. C. voltages and device parameters. Electron and hole surface channel currents are pres- ent simultaneously, a new feature which could provide circuit functions in one physical transistor such as the CMOS inverter and SRAM memory.展开更多
This paper gives the short channel analytical theory of the bipolar field-effect transistor (BiFET) with the drift and diffusion currents separately computed in the analytical theory. As in the last-month paper whic...This paper gives the short channel analytical theory of the bipolar field-effect transistor (BiFET) with the drift and diffusion currents separately computed in the analytical theory. As in the last-month paper which represented the drift and diffusion current by the single electrochemical (potential-gradient) current, the two-dimensional transistor is partitioned into two sections, the source and drain sections, each can operate as the electron or hole emitter or collector under specific combinations of applied terminal voltages. Analytical solution is then obtained in the source and drain sections by separating the two-dimensional trap-free Shockley Equations into two one-dimensional equations parametrically coupled via the surface-electric-potential and by using electron current continuity and hole current continuity at the boundary between the emitter and collector sections. Total and the drift and diffusion components of the electron-channel and hole-channel currents and output and transfer conductances, and the electrical lengths of the two sections are computed and presented in graphs as a function of the D. C. terminal voltages for the model transistor with two identical and connected metal-oxide-silicon-gates (MOS-gates) on a thin pure-silicon base over practical ranges of thicknesses of the silicon base and gate oxide. Deviations of the two-section short-channel theory from the one-section long-channel theory are described.展开更多
This paper describes the short channel theory of the bipolar field-effect transistor (BiFET) by partitioning the transistor into two sections,the source and drain sections,each can operate as the electron or hole em...This paper describes the short channel theory of the bipolar field-effect transistor (BiFET) by partitioning the transistor into two sections,the source and drain sections,each can operate as the electron or hole emitter or collector under specific combinations of applied terminal voltages. Analytical solution is obtained in the source and drain sections by separating the two-dimensional trap-free Shockley Equations into two one-dimensional equations parametrically coupled via the surface-electric-potential and by using electron current continuity and hole current continuity at the boundary between the emitter and collector sections. Total and electron-hole-channel components of the output and transfer currents and conductances, and the electrical lengths of the two sections are computed and presented in graphs as a function of the D. C. terminal voltages for the model transistor with two identical and connected metal-oxide-silicon-gates (MOS-gates) on a thin pure-silicon base over practical ranges of thicknesses of the silicon base and gate oxide. Deviations of the long physical channel currents and conductances from those of the short electrical channels are reported.展开更多
The field-effect transistor is inherently bipolar, having simultaneously electron and hole surface and volume channels and currents. The channels and currents are controlled by one or more externally applied transvers...The field-effect transistor is inherently bipolar, having simultaneously electron and hole surface and volume channels and currents. The channels and currents are controlled by one or more externally applied transverse electric fields. It has been known as the unipolar field-effect transistor for 55-years since Shockley's 1952 invention,because the electron-current theory inevitably neglected the hole current from over-specified internal and boundary conditions, such as the electrical neutrality and the constant hole-electrochemical-potential, resulting in erroneous solutions of the internal and terminal electrical characteristics from the electron channel current alone, which are in gross error when the neglected hole current becomes comparable to the electron current, both in subthreshold and strong inversion. This report presents the general theory, that includes both electron and hole channels and currents. The rectangular ( x, y, z) parallelepiped transistors,uniform in the width direction (z-axis),with one or two MOS gates on thin and thick,and pure and impure base, are used to illustrate the two-dimensional effects and the correct internal and boundary conditions for the electric and the electron and hole electrochemical potentials. Complete analytical equations of the DC current-voltage characteristics of four common MOS transistor structures are derived without over-specification: the 1-gate on semi-infinite-thick impure-base (the traditional bulk transistor), the 1-gate on thin impure-silicon layer over oxide-insulated silicon bulk (SOI) ,the 1-gate on thin impure-silicon layer deposited on insulating glass (SOI TFT), and the 2-gates on thin pure-base (FinFETs).展开更多
This paper describes the drift-diffusion theory of the bipolar field-effect transistor (BiFET) with two identical and connected metal-oxide-silicon-gates (MOS-gates) on a thin-pure-base. Analytical solution is obt...This paper describes the drift-diffusion theory of the bipolar field-effect transistor (BiFET) with two identical and connected metal-oxide-silicon-gates (MOS-gates) on a thin-pure-base. Analytical solution is obtained by partitioning the two-dimensional transistor into two one-dimensional problems coupled by the parametric sur- face-electric-potential. Total and component output and transfer currents and conductances versus D. C. voltages from the drift-diffusion theory, and their deviations from the electrochemical (quasi-Fermi) potential-gradient theory,are presented over practical ranges of thicknesses of the silicon base and gate oxide. A substantial contri- bution from the longitudinal gradient of the square of the transverse electric field is shown.展开更多
The previous report (XI) gave the electrochemical-potential theory of the Bipolar Field-Effect Transistors. This report (XII) gives the drift-diffusion theory. Both treat 1-gate and 2-gate, pure-base and impure-ba...The previous report (XI) gave the electrochemical-potential theory of the Bipolar Field-Effect Transistors. This report (XII) gives the drift-diffusion theory. Both treat 1-gate and 2-gate, pure-base and impure-base, and thin and thick base. Both utilize the surface and bulk potentials as the parametric variables to couple the voltage and current equations. In the present drift-diffusion theory, the very many current terms are identified by their mobility multiplier for the components of drift current,and the diffusivity multiplier for the components of the diffusion current. Complete analytical driftdiffusion equations are presented to give the DC current-voltage characteristics of four common MOS transistor structures. The drift current consists of four terms: 1-D (One-Dimensional) bulk charge drift term, 1-D carrier space-charge drift term,l-D Ex^2 (transverse electric field) drift term,2-D drift term. The diffusion current consists of three terms: 1-D bulk charge diffusion term,l-D carrier space-charge diffusion term,and 2-D diffusion term. The 1-D Ex^2 drift term was missed by all the existing transistor theories, and contributes significantly, as much as 25 % of the total current when the base layer is nearly pure. The 2-D terms come from longitudinal gradient of the longitudinal electric field,which scales as the square of the Debye to Channel length ratio, at 25nm channel length with nearly pure base, (LD/L)^2 = 10^6 but with impurity concentration of 10^18cm^-3 , (LD/L)^2 = 10^-2 .展开更多
This paper reports the intrinsic-structure DC characteristics computed from the analytical electrochemical current theory of the bipolar field-effect transistor (BiFET) with two identical MOS gates on nanometer-thic...This paper reports the intrinsic-structure DC characteristics computed from the analytical electrochemical current theory of the bipolar field-effect transistor (BiFET) with two identical MOS gates on nanometer-thick pure-base of silicon with no generation-recombination-trapping. Numerical solutions are rapidly obtained for the three potential variables,electrostatic and electron and hole electrochemical potentials,to give the electron and hole surface and volume channel currents,using our cross-link two-route or zig-zag one-route recursive iteration algorithms. Boundary conditions on the three potentials dominantly affect the intrinsic-structure DC characteristics,illustrated by examples covering 20-decades of current (10-22 to 10-2 A/Square at 400cm^2/(V · s) mobility for 1.5nm gate-oxide, and 30nm-thick pure-base). Aside from the domination of carrier space-charge-limited drift current in the strong surface channels,observed in the theory is also the classical drift current saturation due to physical pinch-off of an impure-base volume channel depicted by the 1952 Shockley junction-gate field-effect transistor theory,and its extension to complete cut-off of the pure-base volume channel,due to vanishing carrier screening by the few electron and hole carriers in the pure-base,with Debye length (25mm) much larger than device dimension (25nm).展开更多
Two-dimensional(2D) materials have attracted extensive interest due to their excellent electrical, thermal,mechanical, and optical properties. Graphene has been one of the most explored 2D materials. However, its zero...Two-dimensional(2D) materials have attracted extensive interest due to their excellent electrical, thermal,mechanical, and optical properties. Graphene has been one of the most explored 2D materials. However, its zero band gap has limited its applications in electronic devices. Transition metal dichalcogenide(TMDC), another kind of 2D material,has a nonzero direct band gap(same charge carrier momentum in valence and conduction band) at monolayer state,promising for the efficient switching devices(e.g., field-effect transistors). This review mainly focuses on the recent advances in charge carrier mobility and the challenges to achieve high mobility in the electronic devices based on 2DTMDC materials and also includes an introduction of 2D materials along with the synthesis techniques. Finally, this review describes the possible methodology and future prospective to enhance the charge carrier mobility for electronic devices.展开更多
基金Supported by the Fundamental Research Funds for the Central Universities of China
文摘We report a back-gated metal-oxide-ferroelectric-metal (MOFM) field-effect transistor (FET) with lead zirconate titanate (PZT) material, in which an Al doped zinc oxide (AZO) channel layer with an optimized doping concentration of 1% is applied to reduce the channel resistance of the channel layer, thus guaranteeing a large enough load capacity of the transistor. The hysteresis loops of the Pt/PZT/AZO/Ti/Pt capacitor are measured and compared with a Pt/PZT/Pt capacitor, indicating that the remnant polarization is almost 40 μC/cm^2 and the polarization is saturated at 20 V. The measured capacitance-voltage properties are analyzed as a result of the electron depletion and accumulation switching operation conducted by the modulation of PZT on AZO channel resistance caused by the switchable remnant polarization of PZT. The switching properties of the AZO channel layer are also proved by the current-voltage transfer curves measured in the back-gated MOFM ferroelectric FET, which also show a drain current switching ratio up to about 100 times.
基金supported by the National Key Technologies R&D Program,China(Grant No.2009ZX02302-002)the National Natural Science Foundation of China(Grant Nos.61376108,61076076,and 61076068)+2 种基金NSAF,China(Grant No.U1430106)the Science and Technology Commission of Shanghai Municipality,China(Grant No.13NM1400600)Zhuo Xue Plan in Fudan University,China
文摘Organic ferroelectric field-effect transistors (OFeFETs) are regarded as a promising technology for low-cost flexible memories. However, the electrical instability is still a critical obstacle, which limits the commercialization process. Based on already established models for polarization in ferroelectrics and charge transport in OFeFETs, simulation work is performed to determine the influence of polarization fatigue and ferroelectric switching transient on electrical characteristics in OFeFETs. The polarization fatigue results in the decrease of the on-state drain current and the memory window width and thus degrades the memory performance. The output measurements during the ferroelectric switching process show a hysteresis due to the instable polarization. In the on/off measurements, a large writing/erasing pulse frequency weakens the polarization modulation and thus results in a small separation between on- and off-state drain currents. According to the electrical properties of the ferroelectric layer, suggestions are given to obtain optimal electrical characterization for OFeFETs.
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.
基金This work was supported by H2020 RISE-MELON action(I.L.),and by Terra Quantum AG(I.L.,A.R.,and V.M.V.)The work of V.M.V.was supported in part by Fulbright Foundation.
文摘Integrating ferroelectric negative capacitance(NC)into the field-effect transistor(FET)promises to break fundamental limits of power dissipation known as Boltzmann tyranny.However,realizing the stable static negative capacitance in the non-transient non-hysteretic regime remains a daunting task.The problem stems from the lack of understanding of how the fundamental origin of the NC due to the emergence of the domain state can be put in use for implementing the NC FET.Here we put forth an ingenious design for the ferroelectric domain-based field-effect transistor with the stable reversible static negative capacitance.Using dielectric coating of the ferroelectric capacitor enables the tunability of the negative capacitance improving tremendously the performance of the field-effect transistors.
基金This work was partly supported by the National Natural Science Foundation of China(Grant Nos.52122205,51902274,52072324,and 11932016)the Science and Technology Innovation Program of Hunan Province(Grant No.2020RC2077)the Natural Science Foundation of Hunan Province(Grant No.2019JJ50617).
文摘Multilevel ferroelectric field-effect transistors(FeFETs)integrated with HfO_(2)-based ferroelectric thin films demonstrate tremendous potential in high-speed massive data storage and neuromorphic computing applications.However,few works have focused on the stability of the multiple memory states in the HfO_(2)-based FeFETs.Here we firstly report the write/read disturb effects on the multiple memory states in the Hf_(0.5)Zr_(0.5)O_(2)(HZO)-based FeFETs.The multiple memory states in HZO-based FeFETs do not show obvious degradation with the write and read disturb cycles.Moreover,the retention characteristics of the intermediate memory states in HZO-based FeFETs with unsaturated ferroelectric polarizations are better than that of the memory state with saturated ferroelectric polarization.Through the deep analysis of the operation principle of in HZO-based FeFETs,we speculate that the better retention properties of intermediate memory states are determined by the less ferroelectric polarization degradation and the weaker ferroelectric polarization shielding.The experimental and theoretical evidences confirm that the long-term stability of the intermediate memory states in HZO-based FeFETs are as robust as that of the saturated memory state,laying a solid foundation for their practical applications.
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Project supported by the National Natural Science Foundation of China (Grant No.12065015)the Hongliu Firstlevel Discipline Construction Project of Lanzhou University of Technology。
文摘The instability of plasma waves in the channel of field-effect transistors will cause the electromagnetic waves with THz frequency.Based on a self-consistent quantum hydrodynamic model,the instability of THz plasmas waves in the channel of graphene field-effect transistors has been investigated with external magnetic field and quantum effects.We analyzed the influence of weak magnetic fields,quantum effects,device size,and temperature on the instability of plasma waves under asymmetric boundary conditions numerically.The results show that the magnetic fields,quantum effects,and the thickness of the dielectric layer between the gate and the channel can increase the radiation frequency.Additionally,we observed that increase in temperature leads to a decrease in both oscillation frequency and instability increment.The numerical results and accompanying images obtained from our simulations provide support for the above conclusions.
基金supported by Center for BioNano Health-Guardfunded by the Ministry of Science, ICT & Future Planning (MSIP) of Korea as a Global Frontier Project (HGUARD_2013M3A6B2)
文摘A facile approach was demonstrated for fabricating high-performance nonvolatile memory devices based on ferroelectric-gate field effect transistors using a p-type Si nanowire coated with omega-shaped gate organic ferroelectric poly(vinylidene fluoride-trifluoroethylene)(P(VDF-Tr FE)). We overcame the interfacial layer problem by incorporating P(VDF-Tr FE) as a ferroelectric gate using a low-temperature fabrication process. Our memory devices exhibited excellent memory characteristics with a low programming voltage of ±5 V, a large modulation in channel conductance between ON and OFF states exceeding 105, a long retention time greater than 3 9 104 s, and a high endurance of over 105 programming cycles while maintaining an ION/IOFFratio higher than 102.
基金supported by the National Key R&D Program of China(2017YFE0131900)the Natural Science Foundation of Chongqing,China(CSTB2023NSCQ-LZX0087)the National Natural Science Foundation of China(62204242,62005182).
文摘The integration between infrared detection and modern microelectronics offers unique opportunities for compact and high-resolution infrared imaging.However,silicon,the cornerstone of modern microelectronics,can only detect light within a limited wavelength range(<1100 nm)due to its bandgap of 1.12 eV,which restricts its utility in the infrared detection realm.Herein,a photo-driven fin field-effect transistor is presented,which breaks the spectral response constraint of conventional silicon detectors while achieving sensitive infrared detection.This device comprises a fin-shaped silicon channel for charge transport and a lead sulfide film for infrared light harvesting.The lead sulfide film wraps the silicon channel to form a“three-dimensional”infrared-sensitive gate,enabling the photovoltage generated at the lead sulfide-silicon junction to effectively modulate the channel conductance.At room temperature,this device realizes a broadband photodetection from visible(635 nm)to short-wave infrared regions(2700 nm),surpassing the working range of the regular indium gallium arsenide and germanium detectors.Furthermore,it exhibits low equivalent noise powers of 3.2×10^(-12) W·Hz^(-1/2) and 2.3×10^(-11) W·Hz^(-1/2) under 1550 nm and 2700 nm illumination,respectively.These results highlight the significant potential of photo-driven fin field-effect transistors in advancing uncooled silicon-based infrared detection.
文摘Organic ferroelectric memory devices based on field effect transistors that can be configured between two stable states of on and off have been widely researched as the next generation data storage media in recent years.This emerging type of memory devices can lead to a new instrument system as a potential alternative to previous non-volatile memory building blocks in future processing units because of their numerous merits such as cost-effective process,simple structure and freedom in substrate choices.This bi-stable non-volatile memory device of information storage has been investigated using several organic or inorganic semiconductors with organic ferroelectric polymer materials.Recent progresses in this ferroelectric memory field,hybrid system have attracted a lot of attention due to their excellent device performance in comparison with that of all organic systems.In this paper,a general review of this type of ferroelectric non-volatile memory is provided,which include the device structure,organic ferroelectric materials,electrical characteristics and working principles.We also present some snapshots of our previous study on hybrid ferroelectric memories including our recent work based on zinc oxide nanowire channels.
基金supported by the National Key R&D Plan of China(Grant No.2023YFB3210400)the National Natural Science Foundation of China(No.62174101)+2 种基金the Major Scientific and Technological Innovation Project of Shandong Province(2021CXGC010603)the Fundamental Research Funds of Shandong University(2020QNQT001)Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of Shandong,Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of Shandong,the Natural Science Foundation of Qingdao-Original exploration project(No.24-4-4-zrjj-139-jch).
文摘Flexible electronics are transforming our lives by making daily activities more convenient.Central to this innovation are field-effect transistors(FETs),valued for their efficient signal processing,nanoscale fabrication,low-power consumption,fast response times,and versatility.Graphene,known for its exceptional mechanical properties,high electron mobility,and biocompatibility,is an ideal material for FET channels and sensors.The combination of graphene and FETs has given rise to flexible graphene field-effect transistors(FGFETs),driving significant advances in flexible electronics and sparked a strong interest in flexible biomedical sensors.Here,we first provide a brief overview of the basic structure,operating mechanism,and evaluation parameters of FGFETs,and delve into their material selection and patterning techniques.The ability of FGFETs to sense strains and biomolecular charges opens up diverse application possibilities.We specifically analyze the latest strategies for integrating FGFETs into wearable and implantable flexible biomedical sensors,focusing on the key aspects of constructing high-quality flexible biomedical sensors.Finally,we discuss the current challenges and prospects of FGFETs and their applications in biomedical sensors.This review will provide valuable insights and inspiration for ongoing research to improve the quality of FGFETs and broaden their application prospects in flexible biomedical sensing.
文摘This paper describes the foundation underlying the device physics and theory of the semiconductor field effect transistor which is applicable to any devices with two carrier species in an electric field. The importance of the boundary conditions on the device current-voltage characteristics is discussed. An illustration is given of the transfer DCIV characteristics computed for two boundary conditions,one on electrical potential,giving much higher drift-limited parabolic current through the intrinsic transistor, and the other on the electrochemical potentials, giving much lower injection-over-thebarrier diffusion-limited current with ideal 60mV per decade exponential subthreshold roll-off, simulating electron and hole contacts. The two-MOS-gates on thin pure-body silicon field-effect transistor is used as examples
文摘This paper describes the bipolar field-effect transistor (BiFET) and its theory. Analytical solution is ob- tained from partitioning the two-dimensional transistor into two one-dimensional transistors. The analysis employs the parametric surface-electric-potential and the electrochemical (quasi-Fermi) potential-gradient driving force to compute the current. Output and transfer D. C. current and conductance versus voltage are presented over practi- cal ranges of terminal D. C. voltages and device parameters. Electron and hole surface channel currents are pres- ent simultaneously, a new feature which could provide circuit functions in one physical transistor such as the CMOS inverter and SRAM memory.
文摘This paper gives the short channel analytical theory of the bipolar field-effect transistor (BiFET) with the drift and diffusion currents separately computed in the analytical theory. As in the last-month paper which represented the drift and diffusion current by the single electrochemical (potential-gradient) current, the two-dimensional transistor is partitioned into two sections, the source and drain sections, each can operate as the electron or hole emitter or collector under specific combinations of applied terminal voltages. Analytical solution is then obtained in the source and drain sections by separating the two-dimensional trap-free Shockley Equations into two one-dimensional equations parametrically coupled via the surface-electric-potential and by using electron current continuity and hole current continuity at the boundary between the emitter and collector sections. Total and the drift and diffusion components of the electron-channel and hole-channel currents and output and transfer conductances, and the electrical lengths of the two sections are computed and presented in graphs as a function of the D. C. terminal voltages for the model transistor with two identical and connected metal-oxide-silicon-gates (MOS-gates) on a thin pure-silicon base over practical ranges of thicknesses of the silicon base and gate oxide. Deviations of the two-section short-channel theory from the one-section long-channel theory are described.
文摘This paper describes the short channel theory of the bipolar field-effect transistor (BiFET) by partitioning the transistor into two sections,the source and drain sections,each can operate as the electron or hole emitter or collector under specific combinations of applied terminal voltages. Analytical solution is obtained in the source and drain sections by separating the two-dimensional trap-free Shockley Equations into two one-dimensional equations parametrically coupled via the surface-electric-potential and by using electron current continuity and hole current continuity at the boundary between the emitter and collector sections. Total and electron-hole-channel components of the output and transfer currents and conductances, and the electrical lengths of the two sections are computed and presented in graphs as a function of the D. C. terminal voltages for the model transistor with two identical and connected metal-oxide-silicon-gates (MOS-gates) on a thin pure-silicon base over practical ranges of thicknesses of the silicon base and gate oxide. Deviations of the long physical channel currents and conductances from those of the short electrical channels are reported.
文摘The field-effect transistor is inherently bipolar, having simultaneously electron and hole surface and volume channels and currents. The channels and currents are controlled by one or more externally applied transverse electric fields. It has been known as the unipolar field-effect transistor for 55-years since Shockley's 1952 invention,because the electron-current theory inevitably neglected the hole current from over-specified internal and boundary conditions, such as the electrical neutrality and the constant hole-electrochemical-potential, resulting in erroneous solutions of the internal and terminal electrical characteristics from the electron channel current alone, which are in gross error when the neglected hole current becomes comparable to the electron current, both in subthreshold and strong inversion. This report presents the general theory, that includes both electron and hole channels and currents. The rectangular ( x, y, z) parallelepiped transistors,uniform in the width direction (z-axis),with one or two MOS gates on thin and thick,and pure and impure base, are used to illustrate the two-dimensional effects and the correct internal and boundary conditions for the electric and the electron and hole electrochemical potentials. Complete analytical equations of the DC current-voltage characteristics of four common MOS transistor structures are derived without over-specification: the 1-gate on semi-infinite-thick impure-base (the traditional bulk transistor), the 1-gate on thin impure-silicon layer over oxide-insulated silicon bulk (SOI) ,the 1-gate on thin impure-silicon layer deposited on insulating glass (SOI TFT), and the 2-gates on thin pure-base (FinFETs).
文摘This paper describes the drift-diffusion theory of the bipolar field-effect transistor (BiFET) with two identical and connected metal-oxide-silicon-gates (MOS-gates) on a thin-pure-base. Analytical solution is obtained by partitioning the two-dimensional transistor into two one-dimensional problems coupled by the parametric sur- face-electric-potential. Total and component output and transfer currents and conductances versus D. C. voltages from the drift-diffusion theory, and their deviations from the electrochemical (quasi-Fermi) potential-gradient theory,are presented over practical ranges of thicknesses of the silicon base and gate oxide. A substantial contri- bution from the longitudinal gradient of the square of the transverse electric field is shown.
文摘The previous report (XI) gave the electrochemical-potential theory of the Bipolar Field-Effect Transistors. This report (XII) gives the drift-diffusion theory. Both treat 1-gate and 2-gate, pure-base and impure-base, and thin and thick base. Both utilize the surface and bulk potentials as the parametric variables to couple the voltage and current equations. In the present drift-diffusion theory, the very many current terms are identified by their mobility multiplier for the components of drift current,and the diffusivity multiplier for the components of the diffusion current. Complete analytical driftdiffusion equations are presented to give the DC current-voltage characteristics of four common MOS transistor structures. The drift current consists of four terms: 1-D (One-Dimensional) bulk charge drift term, 1-D carrier space-charge drift term,l-D Ex^2 (transverse electric field) drift term,2-D drift term. The diffusion current consists of three terms: 1-D bulk charge diffusion term,l-D carrier space-charge diffusion term,and 2-D diffusion term. The 1-D Ex^2 drift term was missed by all the existing transistor theories, and contributes significantly, as much as 25 % of the total current when the base layer is nearly pure. The 2-D terms come from longitudinal gradient of the longitudinal electric field,which scales as the square of the Debye to Channel length ratio, at 25nm channel length with nearly pure base, (LD/L)^2 = 10^6 but with impurity concentration of 10^18cm^-3 , (LD/L)^2 = 10^-2 .
文摘This paper reports the intrinsic-structure DC characteristics computed from the analytical electrochemical current theory of the bipolar field-effect transistor (BiFET) with two identical MOS gates on nanometer-thick pure-base of silicon with no generation-recombination-trapping. Numerical solutions are rapidly obtained for the three potential variables,electrostatic and electron and hole electrochemical potentials,to give the electron and hole surface and volume channel currents,using our cross-link two-route or zig-zag one-route recursive iteration algorithms. Boundary conditions on the three potentials dominantly affect the intrinsic-structure DC characteristics,illustrated by examples covering 20-decades of current (10-22 to 10-2 A/Square at 400cm^2/(V · s) mobility for 1.5nm gate-oxide, and 30nm-thick pure-base). Aside from the domination of carrier space-charge-limited drift current in the strong surface channels,observed in the theory is also the classical drift current saturation due to physical pinch-off of an impure-base volume channel depicted by the 1952 Shockley junction-gate field-effect transistor theory,and its extension to complete cut-off of the pure-base volume channel,due to vanishing carrier screening by the few electron and hole carriers in the pure-base,with Debye length (25mm) much larger than device dimension (25nm).
基金funded by Australian Research Council discovery project DP140103041Future Fellowship FT160100205
文摘Two-dimensional(2D) materials have attracted extensive interest due to their excellent electrical, thermal,mechanical, and optical properties. Graphene has been one of the most explored 2D materials. However, its zero band gap has limited its applications in electronic devices. Transition metal dichalcogenide(TMDC), another kind of 2D material,has a nonzero direct band gap(same charge carrier momentum in valence and conduction band) at monolayer state,promising for the efficient switching devices(e.g., field-effect transistors). This review mainly focuses on the recent advances in charge carrier mobility and the challenges to achieve high mobility in the electronic devices based on 2DTMDC materials and also includes an introduction of 2D materials along with the synthesis techniques. Finally, this review describes the possible methodology and future prospective to enhance the charge carrier mobility for electronic devices.