Planar Capacitor Research Articles

Планарные емкостные структуры на основе сегнетоэлектрических пленок титаната-станната бария на сапфире для сверхвысокочастотных применений

The structural properties of ferroelectric films of barium titanate-stannate on the sapphire substrates and the microwave characteristics of planar capacitors on their base are investigated. It was found that the composition of the gas ambient during the deposition of the film has a significant effect on the crystal structure, the phase composition of the films and their electrical characteristics. A low level of dielectric loss of planar capacitors with high tunability based on films of barium titanate stannate in the frequency range of 2-60 GHz was demonstrated.

Magnetorheological bio-suspensions membranes: Influence of magnetic flux density on the electrical conductivity and relative dielectric permittivity

Magnetorheological bio-suspensions based membranes are fabricated using a microfiber cloth soaked with a mixture of honey, turmeric powder and carbonyl iron microparticles. Plane capacitors are manufactured by introducing the membranes between two parallel Copper plates. The electrical conductivity and the relative dielectric permittivity of the membranes are measured in a static magnetic field superimposed on an electric field with fixed frequency. The results show that the membranes can be used for fabrication of devices which require a controlled release of the bio-active components found in honey and TP, by fixing the value of magnetic field density.

Entropy Signatures of Topological Phase Transitions

We review the behavior of the entropy per particle in various two-dimensional electronic systems. The entropy per particle is an important characteristic of any many body system that tells how the entropy of the ensemble of electrons changes if one adds one more electron. Recently, it has been demonstrated how the entropy per particle of a two-dimensional electron gas can be extracted from the recharging current dynamics in a planar capacitor geometry. These experiments pave the way to the systematic studies of entropy in various crystal systems including novel two-dimensional crystals such as gapped graphene, germanene and silicene. Theoretically, the entropy per particle is linked to the temperature derivative of the chemical potential of the electron gas by the Maxwell relation. Using this relation, we calculate the entropy per particle in the vicinity of topological transitions in various two-dimensional electronic systems. We show that the entropy experiences quantized steps at the points of Lifshitz transitions in a two-dimensional electronic gas with a parabolic energy spectrum. In contrast, in doubled-gapped Dirac materials, the entropy per particles demonstrates characteristic spikes once the chemical potential passes through the band edges. The transition from a topological to trivial insulator phase in germanene is manifested by the disappearance of a strong zero-energy resonance in the entropy per particle dependence on the chemical potential. We conclude that studies of the entropy per particle shed light on multiple otherwise hidden peculiarities of the electronic band structure of novel two-dimensional crystals.

Magnetic field intensity and [formula omitted] concentration effects on the dielectric properties of magnetodielectric tissues

Microfiber-based tissues are prepared by impregnation of an absorbent cloth with silicone oil mixed with carbonyl iron and various volume concentrations of γ-Fe2O3 nanoparticles. Plane capacitors are manufactured having the microfiber tissues as dielectric materials. The equivalent capacitance (Cp) and resistance (Rp) are measured without a magnetic field, and respectively with a magnetic field superimposed on a medium-frequency electric field. From the measured values of Cp and Rp we determine the absorption-dispersion characteristics, the Cole-Cole diagrams, static and optical relative permittivities, and relaxation times of the tissues. We show that in the presence of the magnetic field superimposed on the electric one, the dielectric properties of the tissues are sensibly influenced by the concentration of γ-Fe2O3 nanoparticles.

Structural and microwave characterization of BaSrTiO3 thin films deposited on semi-insulating silicon carbide

Thin ferroelectric barium strontium titanate (BST) layers of high structure quality have been grown for the first time directly on semi-insulating silicon carbide substrates by RF magnetron sputtering of a ceramic target. The structural and microwave properties of the films were substantially improved by an intermediate annealing of the layers during the growing process. Prepared under this approach, BST films have a well-formed crystal structure, which has a positive effect on their electrical properties, specifically on nonlinearity and dielectric losses. Planar capacitors based on these BST films demonstrate the best combination of high tunability and low losses for BST/SiC structures at microwaves.

Fixed Charge Control of Silylated Surface for Stiction-Free Drying with Surface Energy Reduction Process

Recently, a surface energy reduction process (SERP) for stiction-free drying is used for a high aspect pattern structure like shallow trench isolation (STI). The key technology of SERP is trimethylsilyl (TMS) groups termination of the device surface. To explain the electrical influence of TMS groups was found acceptable by measuring the planar capacitor flat-band voltage shift, and the threshold voltage characteristics of 1x-nm node MOS transistors.

The Study of the Surface Distribution of the Electrooptical Properties of the Medium by Reflected Light

The results of the experimental study of the surface distribution of the electrooptic coefficients of crystals LiNbO3, SBN and PLZT-ceramics are described. The induced birefringence in medium was created by an alternating field. The harmonic analysis of reflected laser light was used. The light was reflected from the front face of the transverse cell of the electro-optical medium. The transverse cells were made in the form of planar and three-dimensional flat capacitors. The homogeneity of the surface distribution of electro-optical coefficients of the medium is estimated.

Magnetodielectric effects in membranes based on magnetorheological bio-suspensions

Controlled release of bio-active components in systems based on magnetorheological suspensions (MRSs) can be achieved by exploiting the magnetodielectric effects aimed at investigating the time dependence of electrical conductivity in the presence of a magnetic field for similar membranes, and where membranes with stable physical properties in time have been manufactured. Here, magnetorheological bio-suspensions (MRBSs) are prepared using a microfiber cloth soaked with carbonyl iron and various concentrations of honey and turmeric powder. Plane capacitors are manufactured having MRSs as dielectric materials. We build and describe an experimental setup for measuring the electrical resistance and the quality factor of the capacitors in a static magnetic field superimposed on an alternating electric field. The measured quantities are then used to obtain the electrical conductivity and dispersion curves of MRSs-based membranes. The results show that the obtained quantities are sensibly influenced by the electric field frequency, magnetic flux density as well as by the ration between honey and turmeric powder concentrations.

Isotropic Oxidation by Plasma Oxidation and Investigation of RIE Induced Effects for Development of 4H-SiC Trench MOSFETs

In this work, we examined the oxidation growth rates of the (0001) Si-face and (11−20) a-faces of 4H-SiC by carrying out oxidation in the 850°C-950 °C temperature range in a plasma afterglow furnace for application to trench MOSFETs. At 900 °C, this method results in almost equal oxide thickness on the Si-face and a-face which would nominally correspond to trench bottom and sidewalls in trench devices. Our results indicate that after NO annealing, the electronic properties of the plasma oxidized SiO2/SiC interface is comparable to control samples with gate oxides formed by dry oxidation at 1150 °C followed by NO annealing. Next, the effect of reactive ion etching (RIE) of 4H-SiC surfaces prior to gate oxidation was investigated using planar 4H-SiC MOS capacitors. Our experiments show that oxidation followed by NO annealing of surfaces with smooth morphology following the RIE step, results in similar interface charge and trap densities as MOS capacitors which did not undergo the RIE etching.

Analysis of 3-Dimensional 4H-SiC MOS Capacitors Grown by Atomic Layer Deposition of Al<sub>2</sub>O<sub>3</sub>

3-Dimensional 4H-SiC metal-oxide-semiconductor capacitors have been fabricated to determine the effect of the sidewall on the characteristics of 3-Dimentional gate structures. Al2O3 deposited by Atomic Layer Deposition (ALD) was used as the gate dielectric layer on the trench structure. The 3-D MOS capacitors exhibit increasing accumulation capacitance with excellent linearity as the sidewall area increases, indicating that ALD results in a highly conformal dielectric film. The capacitance – voltage characteristics also show evidence of a second flatband voltage, located at a higher bias than that seen for purely planar devices on the same sample. We also observe that the oxide capacitance of planar and 3-D MOS capacitors increases with temperature. Finally, we have found that the 3-D MOS capacitor has a weaker temperature dependence of flatband voltage in comparison to the conventional planar MOS capacitor due to the incorporation of the (1120) plane in the sidewall.

Calibration of micro-capacitance measurement system for thermal barrier coating testing.

In order to comprehensively evaluate the thermal barrier coating system of an engine blade, an integrated planar sensor combining electromagnetic coils with planar capacitors is designed, in which the capacitance measurement accuracy of the planar capacitor is a key factor. The micro-capacitance measurement system is built based on an impedance analyzer. Because of the influence of non-ideal factors on the measuring system, there is an obvious difference between the measured value and the actual value. It is necessary to calibrate the measured results and eliminate the difference. In this paper, the measurement model of a planar capacitive sensor is established, and the relationship between the measured value and the actual value of capacitance is deduced. The model parameters are estimated with the least square method, and the calibration accuracy is evaluated with experiments under different dielectric conditions. The capacitance measurement error is reduced from 29% ∼ 46.5% to around 1% after calibration, which verifies the feasibility of the calibration method.

An Electromagnetic/Capacitive Composite Sensor for Testing of Thermal Barrier Coatings.

Thermal barrier coatings (TBCs) can significantly reduce the operating temperature of the aeroengine turbine blade substrate, and their testing technology is very urgently demanded. Due to their complex multi-layer structure, it is hard to evaluate TBCs with a single function sensor. In this paper, an electromagnetic/capacitive composite sensor is proposed for the testing of thermal barrier coatings. The dielectric material is tested with planar capacitor, and the metallic material is tested with electromagnetic coils. Then, the comprehensive test and evaluation of thermal barrier coating system can be realized. The sensor is optimized by means of theoretical and simulation analysis, and the interaction between the planar capacitor and the electromagnetic coil is studied. The experimental system is built based on an impedance analyser and multiplex unit to evaluate the performance of the composite sensor. The transimpedances and capacitances are measured under different coating parameters, such as thickness and permittivity of top coating as well as bond layer conductivity. The experimental results agree with the simulation analysis, and the feasibility of the sensor is proved.

Design and experimental analysis of MEMS-based Ku band phase shifter

PurposeThis paper aims to design a radio frequency micro-electro-mechanical system (RF MEMS)-based phase shifter using chamfered coplanar waveguide (CPW) transmission line (t-line) with open-circuit interdigital metal–air–metal (ID MAM) capacitors.Design/methodology/approachThe proposed phase shifter achieves maximum differential phase shift with low loss at Ku band. The phase shifter is built with one switchable fixed-fixed beam (MEMS switch) on chamfered CPW t-line in series with two planar open-circuit ID MAM capacitors. An equivalent circuit model for the proposed phase shifter is derived, and its parameters are extracted using an electromagnetic (EM) solver.FindingsThe MEMS switch is actuated using an electrostatic method with the calculated residual stress of 44.26 MPa. The fabricated phase shifter exhibits low insertion loss, close to 0.14 dB at 17 GHz, with the maximum phase shift of 15.06°. The return loss is greater than 23 dB between 12 and 18 GHz.Originality/valueThis phase shifter presents a promising solution for low loss applications in the Ku band with a maximum phase shift. As the maximum phase shift of 15.06° is achieved for a unit cell with low insertion loss, the phase shifter is found to be feasible for modern electronically tunable phased arrays used for satellite communication and radar systems.

Real time determination of the laser ablated mass by means of electric field-perturbation measurement

A Nd:YAG ns-pulsed laser was used to ablate Al, Cd and Zn targets, which were placed between the plates of a planar charged capacitor. The plasma generates a transient redistribution of the electrical charges on the plates that can be measured as a voltage drop across a resistor connected to the ground plate. This signal is proportional to the capacitor applied voltage, the distance between the plates and the total number of ions produced in the ablation process which in turn is related to the laser energy and the ablated mass. After a series of pulses, the targets were weighed on a thermogravimetric balance to measure the ablated mass. Our results show that the electrical signal measured on the resistor is univocally related to the ablated mass from the target. Therefore, after a proper calibration depending on the material and the experimental geometry, the electrical signal can be used for real time quantitative measurement of the ablated mass in pulsed laser generated plasma experiments. The experiments were repeated on an aluminum target, with and without the presence of the external electric field in order to determine the possible influence of the applied electric field on the ablated mass.

Capacitance–Frequency Estimates of Border-Trap Densities in Multifin MOS Capacitors

We use capacitance–frequency ( $C$ – $f$ ) measurements to provide lower bound estimates of border-trap densities in multifin MOS capacitors with high-K dielectrics built in Ge and InGaAs fin field effect transistor (FinFET) technologies before and after X-ray irradiation. The $C$ – $f$ method is illustrated for SiO2-based planar MOS capacitors and compared with high-frequency capacitance–voltage measurements. Lower effective border-trap densities are found before and after irradiation for multifin capacitors built in a strained Ge $p$ MOS FinFET technology than for similar devices built using an early-developmental stage InGaAs MOS technology. These results show the utility of $C$ – $f$ measurements in characterizing defect densities in MOS capacitors, particularly when large border-trap densities exist.

Improvement of the Silicon Solar Cell Performance by Integration of an Electric Field Source in the Solar Cell or Solar Module System

This manuscript is about a theoretical modelling of conversion efficiency improvement of a typical polycrystalline Si solar cell in 1D assumptions. The improvement is brought by the increase of the collection of the minority carriers charge in excess. This increase is the consequence of the influence of an electric field provided by the use of the open circuit photovoltage of another silicon solar cell. We assume that it is integrated two silicon solar cells to the system. The first solar cell provides the open circuit photovoltage which is connected to two aluminum planar armatures creating a planar capacitor. The second solar cell is placed under the uniform electric field created between the two aluminum armatures. This work has shown an improvement of the output electric power leading to the increase of the conversion efficiency. We observe an increase of 0.7% of the conversion efficiency of the second silicon solar cell.

Interface charge trapping induced flatband voltage shift during plasma-enhanced atomic layer deposition in through silicon via

A Through Silicon Via (TSV) is a key component for 3D integrated circuit stacking technology, and the diameter of a TSV keeps scaling down to reduce the footprint in silicon. The TSV aspect ratio, defined as the TSV depth/diameter, tends to increase consequently. Starting from the aspect ratio of 10, to improve the TSV sidewall coverage and reduce the process thermal budget, the TSV dielectric liner deposition process has evolved from sub-atmospheric chemical vapour deposition to plasma-enhanced atomic layer deposition (PE-ALD). However, with this change, a strong negative shift in the flatband voltage is observed in the capacitance-voltage characteristic of the vertical metal-oxide-semiconductor (MOS) parasitic capacitor formed between the TSV copper metal and the p-Si substrate. And, no shift is present in planar MOS capacitors manufactured with the same PE-ALD oxide. By comparing the integration process of these two MOS capacitor structures, and by using Elastic Recoil Detection to study the elemental composition of our films, it is found that the origin of the negative flatband voltage shift is the positive charge trapping at the Si/SiO2 interface, due to the positive PE-ALD reactants confined to the narrow cavity of high aspect ratio TSVs. This interface charge trapping effect can be effectively mitigated by high temperature annealing. However, this is limited in the real process due to the high thermal budget. Further investigation on liner oxide process optimization is needed.

In-House fabrication and Electrical characterization of planner si-nanogap

Nanogap is increasingly known to be beneficial, dependable and higher sensing technology. Another possible purpose is to examine a bioactivity and study the reaction of single molecule. It is important to carefully recognize the differences between the sensor surface and electrode in order to incorporate the biological system with nanogap. Also, it crucial to examine the dielectric properties between the planar nanogap with and without a sample. Electrical concentration between the electrodes could be increased due to integrating of microfluidic channel when the sample is being used. This paper is a report on an electrical point of view of planar nanogap capacitor device with comparison of different excitation frequency with and without microfluidic channel. By using 40 nm Si nanogap devices, the sensitivity of nanogap was compared by dropping deionized water and pH 7 onto the target. Experiments were carried out in wide range of frequencies from 1 Hz to 1 MHz at room temperature with 30 mV input signal (0 V, DC, Offset). Both effects of excitation frequency on capacitance sampling with 10 µm microfluidic integration were analyzed.

A Novel Noise-assisted Prognostic Method for Linear Analog Circuits

Integrated analog circuits play a critical role in modern industrial systems. However, research on prognosis of the remaining useful performance (RUP) of analog circuits is rarely reported. This work presents a novel prognostic scheme for analog circuits. In this scheme first a signal feature is extracted from time-domain output waveforms of the circuit during its initial and faulty states. Then, an auxiliary white-noise estimation methodology based on Kalman filter technique estimates the faulty response waveform. As the embedded planar capacitors have a great influence on integrated circuit (IC) miniaturization, performance and reliability, an empirical model based on gradually decreasing trend of its capacitance is introduced. Due to the influence of capacitor degradation, the change in the circuit output waveform is treated as a fault indicator (FI) for failure prognosis. Next, this FI tendency close to the realistic condition is used to identify the circuit degradation trend. Further, in a data-driven prognostic step, a particle filter is used to predict the RUP of the circuit. Finally, studies on two analog filter circuits verify the proposed method.

Comparative study of electrical characteristics for n-type 4H–SiC planar and trench MOS capacitors annealed in ambient NO**Project supported by the National Basic Research Program of China (Grant No. 2015CB759600), the National Natural Science Foundation of China (Grant Nos. 61474113 and 61574140), the Beijing NOVA Program, China (Grant No. Z1611000049161132016071), China Academy of Engineering Physics (CAEP) Microsystem and THz Science and

The interface properties and electrical characteristics of the n-type 4H–SiC planar and trench metal–oxide–semiconductor (MOS) capacitors are investigated by measuring the capacitance voltage and current voltage. The flat-band voltage and interface state density are evaluated by the quasi-static method. It is not effective on further improving the interface properties annealing at 1250°C in NO ambient for above 1 h due to the increasing interface shallow and fast states. These shallow states reduce the effective positive fixed charge density in the oxide. For the vertical MOS capacitors on the () and () faces, the interface state density can be reduced by approximately one order of magnitude, in comparison to the result of the planar MOS capacitors on the (0001) face under the same NO annealing condition. In addition, it is found that Fowler–Nordheim tunneling current occurs at an oxide electric field of 7 MV/cm for the planar MOS device. However, Poole–Frenkel conduction current occurs at a lower electric field of 4 MV/cm for the trench MOS capacitor. This is due to the local field crowded at the trench corner severely causing the electrons to be early captured at or emitted from the SiO2/SiC interface. These results provide a reference for an in-depth understanding of the mobility-limiting factors and long term reliability of the trench and planar SiO2/SiC interfaces.