Direct Capacitance Research Articles

Prediction of electrical properties of GAAFET based on integrated learning model

As device feature sizes continue to decrease and fin field effect transistors reach their physical limits, gate all around field effect transistors (GAAFETs) have emerged with larger gate control areas and stackable characteristics for better suppression of second-order effects such as short-channel effects due to their gate encircling characteristics. Traditional methods for studying the electrical characteristics of devices are mostly based on the technology computer-aided design. Still, it is not conducive to developing new devices due to its time-consuming and inefficient drawbacks. Deep learning (DL) and machine learning (ML) have been well-used in recent years in many fields. In this paper, we propose an integrated learning model that integrates the advantages of DL and ML to solve many problems in traditional methods. This integrated learning model predicts the direct current characteristics, capacitance characteristics, and electrical parameters of GAAFET better than those predicted by DL or ML methods alone, with a linear regression factor (R 2) greater than 0.99 and very small root mean square error. The proposed integrated learning model achieves fast and accurate prediction of GAAFET electrical characteristics, which provides a new idea for device and circuit simulation and characteristics prediction in microelectronics.

Synthesis and characterization of cotton candy-PANI: Enhanced supercapacitance properties

Polyaniline (PANI) is a popular material for making supercapacitor electrodes due to its long-term cycle stability, specific capacitance, conductivity, mechanical robustness, scalability, and viability. All of these characteristics may be improved by introducing new architecture and employing alternative synthetic methods. The current study covers the synthesis and electrochemical performance of the protonated emeraldine salt of a newly architected PANI, which is referred in this article as cotton candy polyaniline (cc-PANI). It was found that the direct current (DC) conductivity and specific capacitance of PANI and cc-PANI electrodes are 1.21 × 10−4 Scm−1, 3.73 × 10−4 Scm−1 and 161.66 Fg-1, 203.33 Fg-1 at a current density of 1Ag-1 in a 1 M H2SO4 electrolyte solution respectively. Further, the static contact angle (CA) was found to be 38.3o and 32.6o for PANI and cc-PANI. Here, a novel designed cc-PANI was effectively synthesised and characterised. This strategy offers new hopes in the realm of PANI with improved supercapacitance qualities.

Floating Tunable Coupler for Scalable Quantum Computing Architectures

We propose a floating tunable coupler that does not rely on direct qubit-qubit coupling capacitances to achieve the zero-coupling condition. We show that the polarity of the qubit-coupler couplings can be engineered to offset the otherwise constant qubit-qubit coupling and attain the zero-coupling condition when the coupler frequency is above or below the qubit frequencies. We experimentally demonstrate these two operating regimes of the tunable coupler by implementing symmetric and asymmetric configurations of the superconducting pads of the coupler with respect to the qubits. Such a floating tunable coupler provides flexibility in designing large-scale quantum processors while reducing the always-on residual couplings.

Capacitance sensor for measuring void fraction in small channels

The paper presents a method for the measurement of void fraction in two-phase flow of liquid and gas phases in small channels by means of capacitance sensor. It was assumed arbitrarily that the small channels are those of diameter less than 10 mm. The capacitance sensor investigated in this paper consisted of two electrodes mounted on the outer wall of a glass pipe, and an electronic circuit for signal detection. The capacitance of two electrodes depends on the mean electric permittivity of the medium between them. The mean permittivity is a function of permittivity of the channel material and the percentage of both phases of different dielectric constants: liquid and gas. In this paper, the void fraction in two-phase flow was determined from frequency deviation of a high-frequency oscillator, in which the capacitance sensor was connected to a resonant circuit with an inductance in parallel. The advantage of this method over other methods based on the direct capacitance measurement (for example, LCR bridge) is that the intermediate steps for the determination of void fraction from the capacitance changes are omitted, and the void fraction can be directly determined from the calibration curve. Changes in the capacitance of electrodes for various void fractions have been determined numerically from the distribution of electric field in this geometry.

Direct Measurement of Junction Capacitance in the Perovskite Solar Cells

Introduction Organic–inorganic halide perovskite solar cell has great attention for its high performance together with easy production and wide variety of the process & flexibility of substrate materials. Here in this research the results of capacitance measurement inside the perovskite device is discussed. Experimental The capacitance of perovskite solar cell was measured by Capacitance Analyzer (VMK-8000 & VK-CA-1000, SPD Inc.) specially designed for our purpose. Results and Discussion Figure 1(upper) shows the constant current charge-discharge testing protocol for the direct measurement of capacitance. Differ from the conventional AC mode impedance analysis, this technique provides the direct capacitance in DC mode without the effect of measuring frequency and the interpretation of equivalent circuit model.Figure 2(lower) shows the change of capacitance and I-V curves of perovskite solar cell before & after 1 sun irradiation aging. The resulting cell performances are as follows. Before aging; Eff=10.4(forward) Eff=12.4(reverse). After aging; Eff=13.5(forward) Eff=15.1(reverse). The change of capacitances are as follows. Before aging; 30.9μF. After aging; 32.5μF. Due to the definition, the change of the capacitance may came from the change of physical gap in between TiO2 layer and perovskite layer.Further chemical and physical properties of these solar cells will also be discussed in related with crystallographic change. Figure 1

Modeling OFF-state harmonics in MOS transistors used as RF switches

In this paper we identify the dominant contribution to the OFF-state distortion of an MOS transistor coming from the overlap regions applying of device-level harmonic balance simulations in a calibrated TCAD setup. Both overlap (Cgs,Cgd) and direct capacitance (Cds) are described with novel physics-based models that are, in conjunction with an analytical Volterra series analysis, capable of describing the harmonics. This includes the dependency on process and device design parameters such as gate oxide thickness, DC gate bias and doping profile properties in the gate overlap region. The new model is compared to the overlap models of BSIM and EKV showing superior accuracy in modeling the harmonics qualitatively and quantitatively (within <3 dBm for the second and <5 dBm for the third harmonic, respectively).

Effect of the scaffold microenvironment on cell polarizability and capacitance determined by probabilistic computations

In living systems, it is frequently stated that form follows function by virtue of evolutionary pressures on organism development, but in the study of how functions emerge at the cellular level, function often follows form. We study this chicken versus egg problem of emergent structure–property relationships in living systems in the context of primary human bone marrow stromal cells cultured in a variety of microenvironments that have been shown to cause distinct patterns of cell function and differentiation. Through analysis of a publicly available catalog of three-dimensional (3D) cell shape data, we introduce a family of metrics to characterize the ‘form’ of the cell populations that emerge from a variety of diverse microenvironments. In particular, measures of form are considered that are expected to have direct significance for cell function, signaling and metabolic activity: dimensionality, polarizability and capacitance. Dimensionality was assessed by an intrinsic measure of cell shape obtained from the polarizability tensor. This tensor defines ellipsoids for arbitrary cell shapes and the thinnest dimension of these ellipsoids, P1, defines a reference minimal scale for cells cultured in a 3D microenvironment. Polarizability governs the electric field generated by a cell, and determines the cell’s ability to detect electric fields. Capacitance controls the shape dependence of the rate at which diffusing molecules contact the surface of the cell, and this has great significance for inter-cellular signaling. These results invite new approaches for designing scaffolds which explicitly direct cell dimensionality, polarizability and capacitance to guide the emergence of new cell functions derived from the acquired form.

An improved apparatus for vapour–liquid equilibria measurement in polymer + solvent systems at higher temperatures: A study of the water + poly(ethylene glycol) system

Recently we designed an apparatus for total pressure measurement in binary polymer + solvent systems. Accurate as it is, the apparatus is limited by its direct capacitance pressure sensor that can operate only at 318.15 K. In this study we tested a new setup that overcomes this limitation with a pressure transducer (MKS Baratron), which can be heated up to 430 K. The main improvement is that the new setup has eliminated solvent vapour condensation in the pressure measurement unit. Other parts of the equipment can easily be kept at temperatures higher than the system temperature with heating tapes. Unlike the ebulliometric method, which is limited by problems arising from the boiling of viscous mixtures, now we can study solutions with higher polymer concentrations. We tested the new setup by measuring the total pressure of binary poly(ethylene glycol) + water mixtures at six isotherms in the (308.15–343.15) K range. Additionally we determined new data for three isotherms (343.15, 353.15, and 363.15) K using ebulliometric method. We then correlated our measurements with both methods using the UNIQUAC–free volume model and compared them with available published data for isotherms 313.15 K and 333.15 K. The agreement with our static measurement results was excellent.

Anomalous effects on radiation detectors and capacitance measurements inside a modified Faraday cage

We present experimental results showing certain anomalies in the measurements performed inside a modified Faraday cage of decay rates of Ra-226, Tl-204 and Sr-90/I-90, of the gamma spectrum of a Cs-137 preparation, and of the capacitance of both a class-I multilayer ceramic capacitor and of the interconnection cable between the radiation detector and the scaler. Decay rates fluctuate significantly up to 5% around the initial value and differently depending on the type of nuclide, and the spectrum photopeak increases in 4.4%. In the case of the capacitor, direct capacitance measurements at 100Hz, 10kHz and 100kHz show variations up to 0.7%, the most significant taking place at 100Hz. In the case of the interconnection cable, the capacitance varies up to 1%. Dispersion also tends to increase inside the enclosure. However, the measured capacitance variations do not explain the variations observed in decay rates.

Dark Current Characterization of SW HgCdTe IRFPAs Detectors on Si Substrate with Long Time Integration

The dark currents of two short wave (SW) HgCdTe infrared focal plane arrays (IRFPA) detectors hybridized with direct injection (DI) readout and capacitance transimpedance amplifier (CTIA) with long time integration were investigated. The cutoff wavelength of the two SW IRFPAs is about 2.6 μm at 84 K. The dark current densities of DI and CTIA samples are approximately 8.0 × 10−12 A/cm2 and 7.2 × 10−10 A/cm2 at 110 K, respectively. The large divergence of the dark current density might arise from the injection efficiency difference of the two readouts. The low injection efficiency of the DI readout, compared with the high injection efficiency of the CTIA readout at low temperature, makes the dark current density of the DI sample much lower than that of the CTIA sample. The experimental value of injection efficiency of the DI sample was evaluated as 1.1% which is consistent with its theoretical value.

Clock generator IP design in 180 nm CMOS technology

This paper describes a clock generator IP implementation in 180 nm CMOS technology. In this work, a self-biased PLL with proposed direct capacitance multiplication has been implemented, with its pros and cons fully analyzed. The bandwidth tracking capability resulting from the self-biased architecture enables the PLL IP to work over a wide frequency range without degrading the jitter performance. The proposed direct capacitance multiplication also reduces the die area significantly for the implementation of the loop filter capacitor. Power supply noise rejection ability has also been analyzed. Potential start-up issue has been explained, together with the proposed solution. Fabricated in SMIC 180 nm CMOS technology, the total PLL IP occupies only 0.078 mm2 including the integrated loop filter and the decoupling capacitors. The measured output frequency ranges from 50 to 600 MHz with the corresponding duty cycle errors <3 %. The chip consumes 4.7 mA under 1.8 V supply while generating 240 MHz output. The in-band phase noise better than ?105 dBc/Hz and phase noise of ?100 dBc/Hz at 1 MHz offset are achieved. The reference spur level is about ?60 dBc.

High Reliability of MEMS Packaged Capacitive Pressure Sensor Employing 3C-SiC for High Temperature

Abstract This study develops the prototype of a micro-electro-mechanical systems (MEMS) packaged capacitive pressure sensor employing 3C-SiC diaphragm for high temperature devices. The 3C-SiC diaphragm is designed with the thicknesses of 1.0 μm and the width and length of 2.0 mm x 2.0 mm. The fabricated sensor is combined with a reliable stainless steel o-ring packaging concept as a simple assembly approach to reduce the manufacturing cost. There is an o-ring seal at the sensor devices an advantageous for high reliability, small size, lightweight, smart interface features and easy maintenance services. The stability and performance of the prototype devices has been tested for three test group and measured by using LCR meter. The prototypes of MEMS capacitive pressure sensor are characterized under static pressure of 5.0 MPa and temperatures up to 500 °C in a stainless steel chamber with direct capacitance measurement. At room temperature (27 °C), the sensitivity of the sensor is 0.0096 pF/MPa in the range of pressure (1.0–5.0 MPa), with nonlinearity of 0.49%. At 300 °C, the sensitivity is 0.0127 pF/MPa, and the nonlinearity of 0.46%. The sensitivity increased by 0.0031 pF/MPa; corresponding temperature coefficient of sensitivity is 0.058%/°C. At 500 °C, the maximum temperature coefficient of output change is 0.073%/°C being measured at 5.0 MPa. The main impact of this work is the ability of the sensor to operate up to 500 °C, compare to the previous work using similar 3C-SiC diaphragm that can operates only 300 °C. The results also show that MEMS packaged capacitive pressure sensor employing 3C-SiC is performed high reliability for high temperature up to 500 °C. In addition, a reliable stainless steel o-ring packaging concept of MEMS packaged capacitive pressure sensor.

Development of high temperature resistant of 500 °C employing silicon carbide (3C-SiC) based MEMS pressure sensor

This works reports a packaged MEMS capacitive pressure sensor (CPS) employing single crystal 3C-SiC thin film as a diaphragm. The details of the design and fabrication steps involved bulk micromachining process. The 3C-SiC-on-Si wafer is back-etched the bulk Si to leave 3C-SC thin film by applied ProTEK PSB coating as a newly photosensitive layer. The ProTEK PSB is exposed into desired pattern of MEMS capacitive pressure sensor and the exposed pattern is developed by developer (ethylene lactate). The photosensitive can be stripped off with strong combination acid such as 2-(1-methoxy)propyl acetate, ethyl acetoacetate and photoacid generator which is attack the exposed ProTEK PSB while unexposed ProTEK PSB areas remain contact the alignment on the wafer surfaces. The prototypes of a MEMS capacitive pressure is packaged for high temperature up to 500 °C and characterized under static pressure of 5.0 MPa in a stainless steel chamber with direct capacitance measurement using LCR meter. The diaphragm of 3C-SiC thin film has the thicknesses of 1.0 µm and the size of 2.0 × 2.0 mm. At room temperature (27 °C), the sensitivity of the sensor is 0.00962 pF/MPa in the range of (1.0---5.0 MPa), with nonlinearity of 0.49 %. At 300 °C, the sensitivity is 0.0127 pF/MPa, and nonlinearity of 0.46 %. The sensitivity increased by 0.0031 pF/MPa, corresponding temperature coefficient of sensitivity is 0.058 %/ °C. At 500 °C, the maximum temperature coefficient of output change is 0.073 %/ °C being red at 5.0 MPa. The main impact of this work is the ability of the sensor to operate up to 500 °C, compare to the previous work using similar 3C-SiC diaphragm that can operates only 400 °C. The main impact of this work is the ability our CPS to operate up to 500 °C and pressure of 5 MPa to surpass the performance of previous work at lower temperature and pressure. In addition, this CPS has reliable stainless steel (SS) o-ring packaging with a direct assembly approach to reduce manufacturing cost and easy installation and maintenance environment.

RETRACTED ARTICLE: A MEMS packaged capacitive pressure sensor employing 3C-SiC with operating temperature of 500 °C

This study develops the prototype of a micro-electro-mechanical systems (MEMS) packaged capacitive pressure sensor employing 3C-SiC thin film as a diaphragm. The details of the design and fabrication steps involved bulk micromachining process. The 3C-SiC-on-Si wafer is back-etched the bulk Si to leave 3C-SC thin film by applied ProTEK PSB coating as a newly photosensitive layer. The ProTEK PSB is exposed into desired pattern of MEMS capacitive pressure sensor and the exposed pattern is developed by developer (ethylene lactate). The photosensitive can be stripped off with strong combination acid such as 2-(1-methoxy)propyl acetate, ethyl acetoacetate and photoacid generator which is attack the exposed ProTEK PSB while unexposed ProTEK PSB areas remain contact the alignment on the wafer surfaces. The prototypes of a MEMS capacitive pressure is packaged for high temperature up to 500 °C and characterized under static pressure of 5.0 MPa in a stainless steel chamber with direct capacitance measurement using LCR meter. The diaphragm of 3C-SiC thin film has the thicknesses of 1.0 µm and the size of 2.0 mm × 2.0 mm. At room temperature (27 °C), the sensitivity of the sensor is 0.00962 pF/MPa in the range of (1.0---5.0 MPa), with nonlinearity of 0.49 %. At 300 °C, the sensitivity is 0.0127 pF/MPa, and nonlinearity of 0.46 %. The sensitivity increased by 0.0031 pF/MPa, corresponding temperature coefficient of sensitivity is 0.058 %/°C. At 500 °C, the maximum temperature coefficient of output change is 0.073 %/°C being red at 5.0 MPa. The main impact of this work is the ability of the sensor to operate up to 500 °C, compare to the previous work using similar 3C-SiC diaphragm that can operates only 400 °C. In addition, a reliable stainless steel o-ring packaging concept is proposed as a simple assembly approach to reduce the manufacturing cost. There is an o-ring seal a this sensor is designed for high reliability, small size, lightweight, smart interface featured and easy cleaning service in the field which is relatively easy to replace without the need for special skill or tools in short period of time.

Enhancement of the Performance of a Transfer Field Electric Machine Operating in the Asynchronous Mode

This paper reports the enhancement of the output power and power factor of a transfer field machine operating in the asynchronous mode by direct capacitance injection into the auxiliary winding of the machine, which is electrically isolated from the main winding but magnetically coupled to it. It is shown that by proper tuning of the injected capacitance, the torque and output power of the machine is markedly enhanced at improved power factor. With the enhanced output power achievable by capacitance injection, the transfer field machine can compare favorably with an equivalent induction motor except that the synchronous speed is inherently limited to half the frequency of the stator mmf wave (ωr = ½ωo)

BDNF Modulates Presynaptic Functions at a Central Synapse

Our brain function relies on the communication between neurons, a process called synaptic transmission. Brain derived neurotrophic factor (BDNF), a member of the neurotrophin family, regulates synaptic transmission in many brain areas and thus may critically influence brain function. The synaptic effect of BDNF may contribute to its well-known roles in regulation of neuronal survival, synapse development, and synaptic plasticity. Despite these important roles, the basic mechanism by which BDNF affects synaptic transmission remains poorly understood. Previous studies suggest that BDNF acts on transmitter release at nerve terminals, the presynaptic component of the synapse. However, the mechanism by which BDNF regulates transmitter release is unclear. In this study we investigate the role of BDNF in presynaptic function by electrophysiological recordings at the calyx of Held nerve terminal. The calyx of Held is a glutamatergic synapse in the auditory brainstem with a large nerve terminal, which allows direct presynaptic patch-clamp recording and membrane capacitance measurement. By recording vesicle fusion with capacitance measurements at this synapse, here we show that acute application of BDNF inhibits exocytosis. This effect is specific to BDNF because application of K252a, an inhibitor of the BDNF receptor, TkB, blocks the actions of BDNF on presynaptic function. Moreover, BDNF inhibits rapid and slow endocytosis, thus providing a regulatory mechanism for vesicle recycling. Furthermore, we recorded the presynaptic calcium current directly at the calyx nerve terminal and found for the first time that BDNF inhibits calcium current. It has been shown previously, that both exo- and endocytosis are regulated by calcium influx. Thus, our findings establish that neurotrophins regulate the function of the nerve terminal via presynaptic calcium channels. Further understanding of these mechanisms will advance our knowledge of synaptic transmission regulation, a process essential for our brain function.

Effects of Side Surface Roughness on Carrier Mobility in Tri-Gate Single Silicon Nanowire Metal–Oxide–Semiconductor Field-Effect Transistors

In this paper, the effects of side surface roughness on mobility behaviors in single-silicon-nanowire metal–oxide–semiconductor field-effect transistors (MOSFETs) are discussed on the basis of intrinsic carrier mobility data obtained by direct split capacitance–voltage (C–V) method measurement for the first time. To investigate the mechanisms that dominate the mobility degradation in narrower nanowires, low-temperature measurements are performed. It is found that phonon scattering has little dependence on nanowire width, indicating that the mobility degradation in our tri-gate nanowire MOSFETs is caused by surface roughness scattering. It is also found by analyzing the nanowire width dependence of mobility that the process-induced roughness on the side surface is the main source of mobility degradation in nanowire pFETs, while the degradation caused by the side surface roughness is negligible in nanowire nFETs.

Investigation on mechanism for instability under drain current stress in amorphous Si–In–Zn–O thin-film transistors

The mechanism for instability against positive bias stress (PBS) in amorphous Si–In–Zn–O (SIZO) thin-film transistors has been investigated by analyzing the subgap density of states (DOSs), which was extracted from multi-frequency method using direct capacitance–voltage measurements. It was found that DOSs including shallow tail states and deep trap states are constant in density as PBS time increases. It indicates that the bulk traps in the SIZO channel layer and the channel/dielectric interfacial traps are not created during the PBS duration. Therefore, the instability against PBS in SIZO thin-film transistors is attributed to the charge trapping by the acceptor-like DOSs.

Relative Permittivity of Carbon Dioxide + Ethanol Mixtures prediction by means of Artificial Neural Networks

CO2 + ethanol mixtures have a huge scientific interest and enormous relevance for many industrial processes. Obtaining of their chemical and physical properties is a fundamental task. Relative permittivity (r) of these mixtures is a key property because allows a better knowledge of the structure and the interactions in other media. In this work predictive values of relative permittivity (r) of carbon dioxide + ethanol mixtures were obtained implementing artificial neural networks (ANNs). They are used successfully in very different fields; therefore it is a very useful tool. In this case the obtained results enhance the ones from the usual multiple linear regression analysis. In both cases mass fraction, pressure and temperature experimental data from a direct capacitance method were used.

Nonlinear effects in transient electrothermal characterization of anatase TiO2 nanowires

As an effective transient thermal characterization technique, the transient electrothermal (TET) technique features a capability of measuring micro∕nanoscale samples of diverse electrical conducting natures. In this work, single anatase titanium dioxide (TiO(2)) nanowires fabricated using the electrospinning method are characterized using the TET technique. Time-dependent nonlinear effect is observed for both rise and fall stages in the voltage-time (U-t) response profile. The coated iridium film and soldered platinum pads possibly compromise the linear Ohmic effect and introduce undesired effects into the whole system. Two quantitative methods: generalized function analysis and direct capacitance derivation, are developed to suppress the nonlinear effect based on U-t profiles. Data processing is performed to determine the thermal diffusivity using global fitting under non-constant electrical heating. The effective thermal diffusivities from modified analysis processes stay in the range from 2 to 6 × 10(-6) m(2)/s. The results from both methods agree well with each other. The general function analysis method is also applicable for samples of short time thermal transport or for an experimental instrument that has relatively long rise time.