Vertical nanowire/nanosheet FETs with a horizontal channel for threshold voltage modulation

A new type of vertical nanowire(VNW)/nanosheet(VNS)FETs combining a horizontal channel(HC)with bulk/back-gate electrode configuration,including Bulk-HC and FD-SOI-HC VNWFET,is proposed and investigated by TCAD simulation.Comparisons were carried out between conventional VNWFET and the proposed devices.FD-SOI-HC VNWFET exhibits better Ion/Ioff ratio and DIBL than Bulk-HC VNWFET.The impact of channel doping and geometric parameters on the electrical character-istic and body factor(γ)of the devices was investigated.Moreover,threshold voltage modulation by bulk/back-gate bias was im-plemented and a largeγis achieved for wide range V_(th)modulation.In addition,results of I_(on)enhancement and Ioff reduction in-dicate the proposed devices are promising candidates for performance and power optimization of NW/NS circuits by adopting dynamic threshold voltage management.The results of preliminary experimental data are discussed as well.

Voltage-modulated polymer nanopore field-effect transistor for multi-sized nanoparticle detection

Solid-state nanopores offer a range of distinct advantages over biological nanopores,such as structural diversity and greater stability and durability;this makes them highly promising for high-resolution nanoparticle sensing.Biological nanopores can exhibit gating characteristics with stress-responsive switches and can demonstrate specificity toward particular molecules.Drawing inspiration from biological nanopores,this paper introduces a novel polymer nanopore with field-effect characteristics,leveraging a conductive polymer in its construction to showcase intriguing gating behavior.Notably,in this device,the polymer layer serves as the gate,enabling precise control over the source–drain current response inside and outside the pore by simply adjusting the gate voltage.This unique feature allows fine-tuning of the nanopore’s sensitivity to nanoparticles of varying sizes and facilitates its operation in multiple modes.Experimental results reveal that the developed polymer nanopore field-effect transistor demonstrates remarkable selectivity in detecting nanoparticles of various sizes under different applied voltages.The proposed single device demonstrates the exceptional ability to detect multiple types of nanoparticle,showcasing its immense potential for a wide range of applications in biological-particle analysis and medical diagnostics.

Spectral Calculation of the Output Voltage of an Inverter with Bipolar Pulse Width Modulation

Converters with pulse width modulation are used for connections between the direct current （DC） and alternating current （AC） networks, e.g., in uninterrupted power supply systems, AC electromotor drives, for powering induction furnaces, in audio technique. Spectrum of signals sampled by pulse amplitude modulation and output voltage spectrum of the converter with pulse width modulation have similar properties. Spectrum of signals sampled by pulse amplitude modulation contains a harmonic of frequency equal to the frequency of the modulating signal and the harmonics of frequencies equal to the sum of frequency of the modulating signal and multiples of the sampling frequency. The output voltage spectrum of the converter with bipolar pulse width modulation contains harmonic of frequency equal to the frequency of the modulating signal and harmonics of frequencies equal to sum of the frequency of the modulating signal and multiples of the frequency of the carrier signal. It also contains harmonics of frequencies equal to the sum of the multiples of the frequency of the modulating signal and the multiples of the carrier signal. The comparison analysis was carried out for the harmonics of the output voltage of the converter with bipolar pulse width modulation in time domain. The dependency of the amplitudes and frequency spectrum on the wave forms of the carrier signal and modulating signal was shown. Similarity of the output voltage spectrum of the converter and signal spectrum sampled by the pulse width modulation was also shown. Key words： Output voltage converter with bipolar pulse width modulation, spectral analysis, Fourier series, carrier signal, reference signal.

A Novel ADC Architecture for Digital Voltage Regulator Module Controllers

The design and implementation of a novel ADC architecture called ring-ADC for digital voltage regulator module controllers are presented. Based on the principle of voltage-controlled oscillators＇ transform from voltage to frequency,the A/D conversion of ring-ADC achieves good linearity and precise calibration against process variations compared with the delay-line ADC. A differential pulse counting discriminator also helps decrease the power consumption of the ring-ADC. It is fabricated with a Chartered 0.35μm CMOS process, and the measurement results of the integral and differential nonlinearity performance are 0.92LSB and 1.2LSB respectively. The maximum gain error measured in ten sample chips is ± 3.85%. With sampling rate of 500kHz and when the voltage regulator module （VRM） works in steady state, the ring-ADC＇s average power consumption is 2.56mW. The ring-ADC is verified to meet the requirements for digital VRM controller application.

IC Implementation of a Programmable CMOS Voltage Reference

A new approach for the design and implementation of a programmable voltage reference based on an improved current mode bandgap voltage reference is presented. The circuit is simulated and fabricated with Chartered 0. 35μm mixed-signal technology. Measurements demonstrate that the temperature coefficient is ± 36. 3ppm/℃ from 0 to 100℃ when the VID inputs are 11110.As the supply voltage is varied from 2.7 to 5V, the voltage reference varies by about 5mV. The maximum glitch of the transient response is about 20mV at 125kHz. Depending on the state of the five VID inputs,an output voltage between 1.1 and 1.85V is programmed in increments of 25mV.

The Design of TZ-2 High Voltage Pulse Modulator

There are a few assistant heating objects included electron cyclotron resonate heating （ ECRH ）. Two 500 kW gyrotrons introduced from Russia were operated to launch 1 MW energy. So two set of TZ-2 high voltage pulse modulators are needed.

Ignition dynamics of radio frequency discharge in atmospheric pressure cascade glow discharge

A cascade glow discharge in atmospheric helium was excited by a microsecond voltage pulse and a pulse-modulated radio frequency(RF) voltage, in which the discharge ignition dynamics of the RF discharge burst was investigated experimentally. The spatio-temporal evolution of the discharge, the ignition time and optical emission intensities of plasma species of the RF discharge burst were investigated under different time intervals between the pulsed voltage and RF voltage in the experiment. The results show that by increasing the time interval between the pulsed discharge and RF discharge burst from 5 μs to 20 μs, the ignition time of the RF discharge burst is increased from 1.6 μs to 2.0 μs, and the discharge spatial profile of RF discharge in the ignition phase changes from a double-hump shape to a bell-shape. The light emission intensity at 706 nm and 777 nm at different time intervals indicates that the RF discharge burst ignition of the depends on the number of residual plasma species generated in the pulsed discharges.

The effect of conductor loss on half-wave voltage and modulation bandwidth of electro-optic modulators

In this paper, we theoretically deduce the expressions of half-wave voltage and 3-dB modulation bandwidth in which conductor loss is taken into account. The results suggest that it will affect the theoretical values of half-wave voltage and bandwidth as well as the optimized electrode's dimension whether considering the conductor loss or not. As an example, we present a Mach-Zehnder (MZ) type polymer waveguide amplitude modulator. The half-wave voltage increases by 1 V and the 3-dB bandwidth decreases by 30% when the conductor loss is taken into account. Besides, the effects of impedance mismatching and velocity mismatching between microwave and light wave on the half-wave voltage, and 3-dB bandwidth are discussed.

Dynamic Frequency Support and DC Voltage Regulation Approach for VSC-MTDC Systems

When an additional frequency control is implemented in the voltage source converter-based multi-terminal high voltage direct current(VSC-MTDC)system,the DC grid is capable of responding to a frequency disturbance in the AC system.However,the original additional frequency control may cause the DC voltage to exceed the limit when providing power for a severe frequency disturbance,threatening the security of the DC system.A novel dynamic additional frequency control strategy for the VSC-MTDC system is developed based on the relationship between the DC voltage and the frequency droop coefficient.A dynamic frequency droop coefficient is designed to adaptively adjust the support power of the DC grid,balancing the frequency regulation of the disturbed AC system and the voltage stability of the DC grid.A DC voltage recovery method based on multi-converter cooperation is proposed to cope with the DC voltage deviation caused by the additional frequency control.Simulations validate the advantages and satisfactory performance of the proposed method during power disturbances with different severities and for the process of DC voltage recovery.

Failure Analysis of Ceramic Substrates Used in High Power IGBT Modules

High voltage power modules are used in numerous applications to build high power converters. Technically, these modules are made of different materials and among them, dielectric materials are organic and inorganic. Organic insulators (gels) are used to avoid corona discharges in the vicinity of connecting wires and high voltage dies (diodes and transistors) and to protect them from moisture and contaminants. Inorganic insulators (ceramic substrates) are used to insulate the high voltage which dies from the grounded elements and to transfer heat to the heat sink. Despite being used since the late 90s, there is a lack of fundamental knowledge about the electrical properties of these substrates. Consequently, manufacturers tend to assure the reliability by over sizing them. As there are no clear rules for how to do that, failures occur, leading to the converter shutdown. The aim of this study is to bring new information about the understanding of the dielectric strength of ceramic materials used in these modules. We have focused our work on the correlation between the mechanical and the dielectric properties of ceramics by using relevant experiments. We provide new information about the impact of existing cracks on the ceramic dielectric failure, according to the electromechanical breakdown model. Our conclusions bring crucial information about the precautions to be taken during manufacturing and implementation of these substrates in power modules to reduce the likelihood of the particular causes of failure.

Partial Discharge Measurement and Analysis in High Voltage IGBT Modules Under DC Voltage

Insulation performance of high voltage IGBT modules is one of the key attributes in power system applications.However,the existing standards of IGBT devices and research on the evaluation of insulation performance of high voltage IGBT modules are insufficient;for example,partial discharge resistance under DC voltage blocking condition is not considered.In this paper,a new test was proposed to allow the measurement of partial discharges in all the components of IGBT modules under DC voltage.The topology of the measuring circuit is arranged in the polarity discrimination way to exclude the interference,and the voltage and discharge current waveforms during the partial discharge process are measured by the wideband time domain measurement technique.According to the proposed test,the discharge phenomenon of the IGBT modules below the rating voltage were detected.A comprehensive waveform analysis on the voltage and discharge current was performed,and the influence of the applied voltage on the waveform parameters was obtained.The waveform parameters are influenced by the applied voltage and insulation structure,which enables the discrimination of the causes of the observed partial discharge in the IGBT module under DC voltage by the waveform analysis technique.Based on the waveform analysis technique,the types and causes of the observed partial discharges were discussed and inferred,and the correctness of the inference was further verified by observation.The proposed test and waveform analysis technique provide the possibility to evaluate and distinguish partial discharges in the high voltage IGBT module under DC voltage,which may be helpful to insulation performance evaluation and insulation defect diagnosis in high voltage IGBT module.

Gate-tunable high-performance broadband phototransistor array of two-dimensional PtSe_(2) on SOI

Two-dimensional(2D)layered materials have attracted extensive research interest in the field of high-performance photodetection due to their high carrier mobility,tunable bandgap,stability,other excellent properties.Herein,we propose a gate-tunable,high-performance,self-driving,wide detection range phototransistor based on a 2D PtSe_(2)on silicon-oninsulator(SOI).Benefiting from the strong built-in electric field of the PtSe_(2)/Si heterostructure,the phototransistor has a fast response time(rise/fall time)of 36.7/32.6μs.The PtSe_(2)/Si phototransistor exhibits excellent photodetection performance over a broad spectral range from ultraviolet to near-infrared,including a responsivity of 1.07 A/W and a specific detectivity of 6.60×10^(9)Jones under 808 nm illumination at zero gate voltage.The responsivity and specific detectivity of PtSe_(2)/Si phototransistor at 5 V gate voltage are increased to 13.85 A/W and 1.90×10^(10) Jones under 808 nm illumination.Furthermore,the fabricated PtSe_(2)/Si phototransistor array shows excellent uniformity,reproducibility,long-term stability in terms of photoresponse performance with negligible variation between pixel cells.The architecture of present PtSe_(2)/Si on SOI platform paves a new way of a general strategy to realize high-performance photodetectors by combining the advantages of both 2D materials and conventional semiconductors which is compatible with current Si-complementary metal oxide semiconductor(CMOS)process.

Harmonic influence analysis of unified power flow controller based on modular multilevel converter

The unified power flow controller(UPFC)based on modular multilevel converter(MMC) is the most creative flexible ac transmission system(FACTS) device. In theory, the output voltage of the series MMC in MMCUPFC can be regulated from 0 to the rated value. However,there would be relatively large harmonics in the output voltage if the voltage modulation ratio is small. In order to analyze the influence of MMC-UPFC on the harmonics of the power grid, the theoretical calculation method and spectra of the output voltage harmonics of MMC are presented. Subsequently, the calculation formulas of the harmonics in the power grid with UPFC are proposed. Based on it, the influence of UPFC on the grid voltage harmonics is evaluated, when MMC-UPFC is operated with different submodular numbers and voltage modular ratios. Eventually, the proposed analysis method is validated using digital simulation. The study results would provide guideline for the design and operation of MMC-UPFC project.

Combination Approach of FEM and Circuit System in IR Drop Analysis and Its Applications

A method was developed to solve the combined system of the current field and the circuit. The ＂super-node＂ was used to transform the matrix for conventional nodal analyses of a circuit system from non-positive definite to positive definite. Then, a positive definite matrix for the overall system was obtained by combining the matrix from the circuit nodal analysis method and the matrix resulted from finite element method （FEM） formulation to solve the FEM fields. This approach has been successfully applied to simulate the electrical potential and current distributions on each metal layer of printed circuit boards （PCBs） and integrated circuit （IC） packages for a given power supply. The simulation results can then be used to analyze the properties of the PCBs and IC packages such as the port resistances and IR drops. The results can also be used to optimize PCB and IC package designs, such as by adjusting the power/ground distribution networks.

A 1.2-V,84-dB∑△ADM in 0.18-μm digital CMOS technology

A low power and low voltage∑△analog-to-digital modulator is realized with digital CMOS technology, which is due to full compensated depletion mode capacitors.Compared with mixed signal technology,this type of modulator is more compatible for pure digital applications.A pseudo-two-stage class-AB OTA is used in switchedcapacitor integrators for low voltage and low power.The modulator is realized in standard SMIC 0.18μm 1P6M digital CMOS technology.Measured results show that with 1.2 V supply voltage and a 6 MHz sample clock,the dynamic range of the modulator is 84 dB and the total power dissipation is 2460μW.