The GaN HEMT is a potential candidate for RF applications due to the high frequency and large power handling capability.To ensure the quality of the communication signal,linearity is a key parameter during the system ...The GaN HEMT is a potential candidate for RF applications due to the high frequency and large power handling capability.To ensure the quality of the communication signal,linearity is a key parameter during the system design.However,the GaN HEMT usually suffers from the nonlinearity problems induced by the nonlinear parasitic capacitance,transconductance,channel transconductance etc.Among them,the transconductance reduction is the main contributor for the nonlinearity and is mostly attributed to the scattering effect,the increasing resistance of access region,the self-heating effect and the trapping effects.Based on the mechanisms,device-level improvement methods of transconductance including the trapping suppression,the nanowire channel,the graded channel,the double channel,the transconductance compensation and the new material structures have been proposed recently.The features of each method are reviewed and compared to provide an overview perspective on the linearity of the GaN HEMT at the device level.展开更多
针对电力应用场景中电磁脉冲导致芯片性能异常退化、芯片内MOSFET(Metal Oxide Semiconductor Field Effect Transistor)等器件失效机理不清晰等问题,本研究采用幅值和宽度分别为8 V和100 ns的TLP(Transmission Line Pulse)脉冲施加至5 ...针对电力应用场景中电磁脉冲导致芯片性能异常退化、芯片内MOSFET(Metal Oxide Semiconductor Field Effect Transistor)等器件失效机理不清晰等问题,本研究采用幅值和宽度分别为8 V和100 ns的TLP(Transmission Line Pulse)脉冲施加至5 V NMOS器件栅氧层,测量了不同脉冲循环次数下器件输出特性曲线I d V d和转移特性曲线I d V g,通过分析不同TLP脉冲条件下跨导的变化规律研究了阈值电压和载流子迁移率随TLP脉冲个数的退化规律。研究结果表明,相同漏电压V d和栅极电压V g下,器件漏电流I d随TLP脉冲次数的增加而升高;TLP脉冲导致阈值电压V T降低显著,施加20000次TLP脉冲后V T降低约25.66%;TLP脉冲造成器件阈值电压的变化量呈指数升高,通过拟合指数为0.11~0.15;TLP脉冲对沟道内载流子迁移率的影响不明显。展开更多
In order to obtain the multiple-feedback filter with simpler structure and electronic control,this paper first derives nodal admittance matrix(NAM)equation of the multiple-feedback filter.Furthermore,in accordance wit...In order to obtain the multiple-feedback filter with simpler structure and electronic control,this paper first derives nodal admittance matrix(NAM)equation of the multiple-feedback filter.Furthermore,in accordance with the pathological models of the operational transconductance amplifier(OTA)and second generation current-controlled conveyor(CCCII),the multiplefeedback filter based on OTAs and CCCIIs are respectively synthesized by the NAM expansion method.The filter employing three OTAs has eight equivalent realizations and the filter employing three CCCIIs has 16 equivalent realizations.24 different forms of the current-mode filters are synthesized in all.fo and Q of the synthesized filters can be tuned by tuning bias currents of the active elements.The hand analysis and computer analysis are included to support the method to be utilized.展开更多
This paper presents a new current-mode single input multi output (SIMO) type biquad employing one voltage differencing transconductance amplifier (VDTA), two grounded capacitors and a single grounded resistor. The con...This paper presents a new current-mode single input multi output (SIMO) type biquad employing one voltage differencing transconductance amplifier (VDTA), two grounded capacitors and a single grounded resistor. The configuration realizes all basic filter functions (i.e. Low Pass (LP), High Pass (HP), Band Pass (BP), Notch (BR) and All Pass (AP)). The natural frequency (ω0) and bandwidth (BW) are independently tunable. The workability of proposed configuration has been verified using SPICE simulation with TSMC CMOS 0.18 μm process parameters.展开更多
An analytic drain current model is presented for doped short-channel double-gate MOSFETs with a Gaussian-like doping profile in the vertical direction of the channel. The present model is valid in linear and satura- t...An analytic drain current model is presented for doped short-channel double-gate MOSFETs with a Gaussian-like doping profile in the vertical direction of the channel. The present model is valid in linear and satura- tion regions of device operation. The drain current variation with various device parameters has been demonstrated. The model is made more physical by incorporating the channel length modulation effect. Parameters like transcon- ductance and drain conductance that are important in assessing the analog performance of the device have also been formulated. The model results are validated by numerical simulation results obtained by using the commercially available ATLAS^TM, a two dimensional device simulator from SILVACO.展开更多
To meet the demands for a number of LEDs,a novel charge pump circuit with current mode control is proposed.Regulation is achieved by operating the current mirrors and the output current of the operational transconduct...To meet the demands for a number of LEDs,a novel charge pump circuit with current mode control is proposed.Regulation is achieved by operating the current mirrors and the output current of the operational transconductance amplifier.In the steady state,the input current from power voltage retains constant,so reducing the noise induced on the input voltage source and improving the output voltage ripple.The charge pump small-signal model is used to describe the device’s dynamic behavior and stability.Analytical predictions were verified by Hspice simulation and testing.Load driving is up to 800 mA with a power voltage of 3.6 V,and the output voltage ripple is less than 45 mV.The output response time is less than 8μs,and the load current jumps from 400 to 800 mA.展开更多
A bimodal effect of transconductance was observed in narrow channel PDSOI sub-micron H-gate PMOSFETs,which was accompanied with the degeneration of device performance.This paper presents a study of the transconductanc...A bimodal effect of transconductance was observed in narrow channel PDSOI sub-micron H-gate PMOSFETs,which was accompanied with the degeneration of device performance.This paper presents a study of the transconductance bimodal effect based on the manufacturing process and electrical properties of those devices.It is shown that this effect is caused by a diffusion of donor impurities from the NC region of body contact to the PC poly gate at the neck of the H-gate,which would change the work function differences of the polysilicon gate and substrate.This means that the threshold voltage of the device is different in the width direction,which means that there are parasitic transistors paralleled with the main transistor at the neck of the H-gate.The subsequent devices were fabricated with layout optimization,and it is demonstrated that the bimodal transconductance can be eliminated by mask modification with NC implantation more than 0.2 m away from a poly gate.展开更多
A 2 nd transconductance subharmonic receiver for 245 GHz spectroscopy sensor applications has been proposed. The receiver consists of a 245 GHz on-chip folded dipole antenna, a CB（common base） LNA, a 2 nd transcondu...A 2 nd transconductance subharmonic receiver for 245 GHz spectroscopy sensor applications has been proposed. The receiver consists of a 245 GHz on-chip folded dipole antenna, a CB（common base） LNA, a 2 nd transconductance SHM（subharmonic mixer）, and a 120 GHz push-push VCO with 1/64 divider. The receiver is fabricated in f;/f;= 300/500 GHz SiGe:C BiCMOS technology. The receiver dissipates a low power of 288 mW.Integrated with the on-chip antenna, the receiver is measured on-chip with a conversion gain of 15 dB, a bandwidth of 15 GHz, and the chip will be utilized in PCB board design for gas spectroscopy sensor application.展开更多
We investigate the transient behavior of an n-type double gate negative capacitance junctionless tun- nel field effect transistor （NC-JLTFET）. The structure is realized by using the work-function engineering of meta...We investigate the transient behavior of an n-type double gate negative capacitance junctionless tun- nel field effect transistor （NC-JLTFET）. The structure is realized by using the work-function engineering of metal electrodes over a heavily doped n＋ silicon channel and a ferroelectric gate stack to get negative capacitance be- havior. The positive feedback in the electric dipoles of ferroelectric materials results in applied gate bias boosting. Various device transient parameters viz. transconductance, output resistance, output conductance, intrinsic gain, intrinsic gate delay, transconductance generation factor and unity gain frequency are analyzed using ac analysis of the device. To study the impact of the work-function variation of control and source gate on device performance, sensitivity analysis of the device has been carried out by varying these parameters. Simulation study reveals that it preserves inherent advantages of charge-plasma junctionless structure and exhibits improved transient behavior as well.展开更多
A rail-to-rail amplifier with constant transconductance,intended for audio processing,is presented.The constant transconductance is obtained by a constant current technique based on the input differential pairs operat...A rail-to-rail amplifier with constant transconductance,intended for audio processing,is presented.The constant transconductance is obtained by a constant current technique based on the input differential pairs operating in the weak inversion region.MOSFETs working in the weak inversion region have the advantages of low power and low distortion.The proposed rail-to-rail amplifier,fabricated in a standard 0.35μm CMOS process,occupies a core die area of 75×183μm2.Measured results show that the maximum power consumption is 85.37μW with a supply voltage of 3.3 V and the total harmonic distortion level is 1.2%at 2 kHz.展开更多
基金supported by the Shenzhen Science and Technology Program on Key Basic Research Project undergrant JCYJ20210324120409025the National Natural Science Foundation of China under grant 61904135。
文摘The GaN HEMT is a potential candidate for RF applications due to the high frequency and large power handling capability.To ensure the quality of the communication signal,linearity is a key parameter during the system design.However,the GaN HEMT usually suffers from the nonlinearity problems induced by the nonlinear parasitic capacitance,transconductance,channel transconductance etc.Among them,the transconductance reduction is the main contributor for the nonlinearity and is mostly attributed to the scattering effect,the increasing resistance of access region,the self-heating effect and the trapping effects.Based on the mechanisms,device-level improvement methods of transconductance including the trapping suppression,the nanowire channel,the graded channel,the double channel,the transconductance compensation and the new material structures have been proposed recently.The features of each method are reviewed and compared to provide an overview perspective on the linearity of the GaN HEMT at the device level.
文摘针对电力应用场景中电磁脉冲导致芯片性能异常退化、芯片内MOSFET(Metal Oxide Semiconductor Field Effect Transistor)等器件失效机理不清晰等问题,本研究采用幅值和宽度分别为8 V和100 ns的TLP(Transmission Line Pulse)脉冲施加至5 V NMOS器件栅氧层,测量了不同脉冲循环次数下器件输出特性曲线I d V d和转移特性曲线I d V g,通过分析不同TLP脉冲条件下跨导的变化规律研究了阈值电压和载流子迁移率随TLP脉冲个数的退化规律。研究结果表明,相同漏电压V d和栅极电压V g下,器件漏电流I d随TLP脉冲次数的增加而升高;TLP脉冲导致阈值电压V T降低显著,施加20000次TLP脉冲后V T降低约25.66%;TLP脉冲造成器件阈值电压的变化量呈指数升高,通过拟合指数为0.11~0.15;TLP脉冲对沟道内载流子迁移率的影响不明显。
基金Supported by the Shaanxi Provincial Key Research and Development Program,China(2018NY-158).
文摘In order to obtain the multiple-feedback filter with simpler structure and electronic control,this paper first derives nodal admittance matrix(NAM)equation of the multiple-feedback filter.Furthermore,in accordance with the pathological models of the operational transconductance amplifier(OTA)and second generation current-controlled conveyor(CCCII),the multiplefeedback filter based on OTAs and CCCIIs are respectively synthesized by the NAM expansion method.The filter employing three OTAs has eight equivalent realizations and the filter employing three CCCIIs has 16 equivalent realizations.24 different forms of the current-mode filters are synthesized in all.fo and Q of the synthesized filters can be tuned by tuning bias currents of the active elements.The hand analysis and computer analysis are included to support the method to be utilized.
文摘This paper presents a new current-mode single input multi output (SIMO) type biquad employing one voltage differencing transconductance amplifier (VDTA), two grounded capacitors and a single grounded resistor. The configuration realizes all basic filter functions (i.e. Low Pass (LP), High Pass (HP), Band Pass (BP), Notch (BR) and All Pass (AP)). The natural frequency (ω0) and bandwidth (BW) are independently tunable. The workability of proposed configuration has been verified using SPICE simulation with TSMC CMOS 0.18 μm process parameters.
文摘An analytic drain current model is presented for doped short-channel double-gate MOSFETs with a Gaussian-like doping profile in the vertical direction of the channel. The present model is valid in linear and satura- tion regions of device operation. The drain current variation with various device parameters has been demonstrated. The model is made more physical by incorporating the channel length modulation effect. Parameters like transcon- ductance and drain conductance that are important in assessing the analog performance of the device have also been formulated. The model results are validated by numerical simulation results obtained by using the commercially available ATLAS^TM, a two dimensional device simulator from SILVACO.
基金supported by the National Natural Science Foundation of China(No.60876023)
文摘To meet the demands for a number of LEDs,a novel charge pump circuit with current mode control is proposed.Regulation is achieved by operating the current mirrors and the output current of the operational transconductance amplifier.In the steady state,the input current from power voltage retains constant,so reducing the noise induced on the input voltage source and improving the output voltage ripple.The charge pump small-signal model is used to describe the device’s dynamic behavior and stability.Analytical predictions were verified by Hspice simulation and testing.Load driving is up to 800 mA with a power voltage of 3.6 V,and the output voltage ripple is less than 45 mV.The output response time is less than 8μs,and the load current jumps from 400 to 800 mA.
文摘A bimodal effect of transconductance was observed in narrow channel PDSOI sub-micron H-gate PMOSFETs,which was accompanied with the degeneration of device performance.This paper presents a study of the transconductance bimodal effect based on the manufacturing process and electrical properties of those devices.It is shown that this effect is caused by a diffusion of donor impurities from the NC region of body contact to the PC poly gate at the neck of the H-gate,which would change the work function differences of the polysilicon gate and substrate.This means that the threshold voltage of the device is different in the width direction,which means that there are parasitic transistors paralleled with the main transistor at the neck of the H-gate.The subsequent devices were fabricated with layout optimization,and it is demonstrated that the bimodal transconductance can be eliminated by mask modification with NC implantation more than 0.2 m away from a poly gate.
基金Project supported by the Zhejiang National Natural Science Foundation of China(No.LQ17F040001)the Key Laboratory Open Project Fund of Southeast University,China(No.K201817)
文摘A 2 nd transconductance subharmonic receiver for 245 GHz spectroscopy sensor applications has been proposed. The receiver consists of a 245 GHz on-chip folded dipole antenna, a CB（common base） LNA, a 2 nd transconductance SHM（subharmonic mixer）, and a 120 GHz push-push VCO with 1/64 divider. The receiver is fabricated in f;/f;= 300/500 GHz SiGe:C BiCMOS technology. The receiver dissipates a low power of 288 mW.Integrated with the on-chip antenna, the receiver is measured on-chip with a conversion gain of 15 dB, a bandwidth of 15 GHz, and the chip will be utilized in PCB board design for gas spectroscopy sensor application.
文摘We investigate the transient behavior of an n-type double gate negative capacitance junctionless tun- nel field effect transistor （NC-JLTFET）. The structure is realized by using the work-function engineering of metal electrodes over a heavily doped n＋ silicon channel and a ferroelectric gate stack to get negative capacitance be- havior. The positive feedback in the electric dipoles of ferroelectric materials results in applied gate bias boosting. Various device transient parameters viz. transconductance, output resistance, output conductance, intrinsic gain, intrinsic gate delay, transconductance generation factor and unity gain frequency are analyzed using ac analysis of the device. To study the impact of the work-function variation of control and source gate on device performance, sensitivity analysis of the device has been carried out by varying these parameters. Simulation study reveals that it preserves inherent advantages of charge-plasma junctionless structure and exhibits improved transient behavior as well.
基金Project supported by the Science and Technology Program of Tianjin,China(No08ZCKFGX00200)
文摘A rail-to-rail amplifier with constant transconductance,intended for audio processing,is presented.The constant transconductance is obtained by a constant current technique based on the input differential pairs operating in the weak inversion region.MOSFETs working in the weak inversion region have the advantages of low power and low distortion.The proposed rail-to-rail amplifier,fabricated in a standard 0.35μm CMOS process,occupies a core die area of 75×183μm2.Measured results show that the maximum power consumption is 85.37μW with a supply voltage of 3.3 V and the total harmonic distortion level is 1.2%at 2 kHz.
