Papers by Keyword: Capacitors

Abstract: This work proposes a linear, area‑based component separation method to extract an effective trench sidewall capacitance from C-V measurements of 4H‑SiC UMOS capacitors. Devices were fabricated with two gate‑oxide schemes LPCVD TEOS and low‑temperature oxidation of LPCVD polysilicon and characterized by I-V and C-V measurements. Planar capacitors show breakdown strength above 9 MV/cm. Least‑squares decomposition of layout‑dependent capacitances enabled the separation of mesa, sidewall and bottom contributions. Additionally, this applying this approach revealed trench-pitch dependent depletion and larger wafer‑level thickness variation for the polysilicon‑oxidation flow. Reconstruction errors up to 20 % indicate that spacing‑dependent depletion, corner curvature, fringe and field‑oxide capacitances exceed the simple parallel‑capacitor model.

Abstract: In this work, PVDF/BaTiO₃ nanocomposites consisting of polyvinylidene fluoride (PVDF) as matrix and BaTiO₃ (BT) as fillers were prepared by ball milling and hot-pressing process. It is known that nanofillers content and frequency affect the effective dielectric permittivity of the nanocomposites materials. Therefore, a developed model based on deep neural network (DNN) was used to study the effect of the input parameters on the dielectric permittivity of the nanocomposites. The volume fraction (vol%) of BT and frequency of alternating current (AC) were selected as the input parameters and the effective dielectric permittivity as the output response. The results show that the developed DNN model was able to predict the effective dielectric permittivity of PVDF/BT nanocomposites with a correlation coefficient (R) of 0.997. Thus, our study confirmed the accuracy and efficiency of the developed DNN model for predicting the relative dielectric permittivity of PVDF/BT nanocomposites.

Abstract: The effect of surface treatments prior to the deposition of Al₂O₃ is performed on 4H-SiC MOS capacitors and MOSFETs. 40 nm of Al₂O₃ were deposited on 4H-SiC using atomic layer deposition (ALD) as a gate dielectric. Different surface treatments were used to investigate the capacitance-voltage and current-voltage characteristics on MOS capacitors and MOSFETs respectively, including the important parameters such as interface state density, flat band voltage, threshold voltage and field-effect mobility. Forming gas annealing and rapid oxidation processes were found to be effective in reducing the interface state density and results in high field-effect mobility with peak field-effect mobility of 130 cm²Vs^-1. The experimental results obtained manifest that the surface treatment prior to Al₂O₃ deposition is critical to producing high performance of 4H-SiC MOSFETs.

Abstract: This article presents theory of The design of medium sized voltage capacitor in order to improve the Power Factor Value to AC motor. In present, the electrical power system has focus on improving the Power Factor significantly because it is the major key to increase or decrease the applicable expenses. The power system that has low power factor will have a lot of loss to system, especially when electrical voltage is on voltage medium. When power factor has been adjusted, the system can take more loads and electrical power loss is decreased. It also decreases voltage in power line and decreases electrical bills at the same time. This article presents the theory to analyze data from motor that needs to adjust a power factor so that it pass electricity authority standard by considering the efficiency of the motor so that the consumers do not have to pay the penalty of the Power Factor Value differences to the Electricity Authority. Furthermore, it can help decrease the bills of unstandardized electrical power which occurred in the system and enable the system to take more loads at the same time.

Abstract: In this study, we compare the electrical properties of MOS capacitors fabricated on different surface morphologies. Comparing a standard, low-roughness (<1nm), surface with one with a roughness of ~40nm, characterized by big macrosteps and large terraces. We compared the two surfaces for different thermal oxide thicknesses, ranging from d_Ox = 3.6 nm to d_Ox = 32 nm. The extracted interface state traps (D_it) shows a small, but systematic, decrease of ~10-15 % for the samples with macrosteps.

Abstract: Polymer-ceramic composites have been pursued as the most promising dielectric materials for embedded capacitors in the organic package. In this study, ceramic fillers such as Calcium Copper Titanate (CCTO) was used to produce epoxy thin film composites for the purpose to replace capacitor made of ceramic materials. Spin coating technique was used to produce epoxy thin film composites. The effect of fillers loading on tensile and dielectric properties of the epoxy thin film composites were determined. Results showed that epoxy thin film with 20 vol% filler loading showed good dielectric properties. However, an increase of the fillers content caused reduction in the tensile properties due to filler agglomeration and voids. Dielectric constants and dielectric losses of epoxy/inorganic composite films generally increase with addition of filler.

Abstract: The power energy storage in battery transfers to capacitors through thyristor in hybrid energy storage, which makes the instantaneous power amplified. As the switch in Hybrid energy storage, the thyristor must satisfy its opening requirements , besides, the characteristics of the hybrid energy storage system is considered to design the width of trigger pulse, otherwise the thyristor can’t be opened that leads to failure of energy transfer. In this paper, the model of the system is established, the function of current to time is derived from the model, and then the minimum width of trigger pulse is calculated out. The simulation and experiment results are presented, which match with the designation well.

Abstract: Nonlinear dielectric lines have been tested for use in RF generation. Although they have presented a reasonable success in the frequency range between 250 and 400 MHz, their main limitation is the dielectric losses of barium titanate (BT) tiles used as nonlinear medium in these lines, which prevents from achieving higher frequencies. The solution for this appears to be the search for a new dielectric. Herein, we are proposing the use of a piezoelectric titanate-based ceramics known as PZT (lead zirconate titanate), which appears to have lower dielectric losses than BT slabs. In this paper, loss characterization tests of the PZT ceramics are compared with BT in the MHz frequency range. Also, we have investigated and compared the nonlinearity properties of the dielectrics by varying the DC applied voltage and temperature.

Abstract: Activated carbons were prepared from coconut shell by chemical activation method and utilized as electrode materials for electrochemical double layer capacitor (EDLC). A preliminary characteristic of activated carbon from coconut shell includes the Brunnaeur Emmett Teller (BET) analysis and cyclic voltammetry measurements. The BET surface area is not affected by the variation of activation temperature as both of the samples showed BET surface area of about 850-870 m2g-1. The N2 adsorption–desorption isotherms showed that the sample exhibited type I characteristics according to IUPAC classification, which confirms its micro-porosity. Compared with the un-activated carbon samples, the activated ones exhibited the better electrochemical properties with a specific capacitance of 150 F g−1 at a scan rate of 2 mV s−1. The good performance of activated carbon is attributed to the enhancement of surface area due to the KOH pretreatment which can open new pores accessible for the ionic transport

Abstract: The combination of nanoparticles with high relative permittivity and polymers with high dielectric strength offers a potential to obtain processable nanocomposites with high dielectric performance. In this work, polyvinylidene fluoride (PVDF)-barium titanate (BT) nanocomposites were prepared by spin-coating technique. The surface of BT nanoparticles was treated by titanate coupling agent NDZ101. The dielectric and energy storage properties of the system were studied as a function of BT content. The experimental results showed that the dielectric constant of the nanocomposites increased with the increase of BT content. Although pure PVDF material has the strongest dielectric breakdown strength, the discharged energy storage density Ue of the nanocomposites was greatly improved from 2.8 J/cm³ in pure PVDF film to 6.2 J/cm³ in PVDF/20 wt% BT film; due to larger polarization of the nanocomposite.