Dielectric Material In Order Research Articles

Study of Nb2O5 High-k Dielectric Material Deposited By Atomic Layer Deposition for Metal-Insulator-Metal Capacitor

Metal-Insulator-Metal (MIM) capacitors are important components in many electronic devices, including memory devices, filters, and oscillators. The performance of these devices depends strongly on the electrical properties of the dielectric layer. The application of new high-k materials can improve the properties of modern capacitors such as leakage current and capacitance density. However, it is necessary to understand the deposition conditions of both electrode and dielectric materials in order to master the dielectric properties in future MIM capacitors.One potentially interesting high-k material is niobium pentoxide (Nb2O5) with a wide band gap (3.6 eV) and high refractive index (n=2.3 @633 nm) deposited by Atomic Layer Deposition (ALD) using niobium (V) ethoxide as niobium precursor at 180°C and H2O as reaction agent and oxygen source. Nb2O5 films were deposited directly on a silicon (Si 100) substrate or on a 10nm of titanium nitride (deposited by ALD on Si substrate, n=1.4@633 nm). The Nb2O5 films were deposited with a good film thickness uniformity on the 6-inches of the wafers with a thickness ranging from 20 to 60 nm on each sample. The deposition was done under a suitable ALD temperature of 200-300 °C. In order to investigate the film growth, structure, morphology and optical properties, the samples were characterized by spectroscopic ellipsometry (SE), scanning electron microscopy (SEM), X-Ray diffraction (XRD) and atomic force microscopy (AFM). The as-deposited films were then annealed in a furnace at temperature ranging from 500 to 650°C under N2 atmosphere.Subsequently, a MIM structure (Al/Nb2O5/TiN) was produced by adding a second aluminum layer deposited at 250°C on a Nb2O5/TiN/Si stack by the sputtering method. The surface of the second electrodes was aimed to have 0.1-1.0 mm2 to confirm the surface dependency of the capacitance value. The electrical properties of Nb2O5 dielectric layer such as dielectric constant, breakdown voltage and leakage current at possible user voltage were measured on this last structure. The low leakage current density is desirable for MIM capacitors as it helps to minimize energy loss and increase the energy storage capabilities of the capacitors. The obtained J-E curve was compared to some electrical conduction mechanisms to identify its electrical conduction behaviors. The barrier height of the F-N tunneling mechanism was determined by fitting the experimental data to the F-N equation. These measurements indicate that the electrical properties of the Nb2O5 material produced by ALD with specific settings are promising for the application in capacitors. These results provide new insight into our understanding of the application of Nb2O5 realized by ALD for the MIM capacitor.

Selection of a suitable environmentally friendly (non-toxic) etching solution in the electroless metallisation of ABS polymers

ABSTRACT Electroless metallisation is a modern method for obtaining thin layers of metals and their alloys on various dielectric materials, which are increasingly used in various industries. One of the important stages in the pretreatment of the polymers for the chemical processes is the etching operation. It ensures surface roughening of the dielectric materials in order to improve the adhesion strength between the electroless deposited metal coating and the acrylonitrile–butadiene-styrene (ABS) substrate. Most often, this operation in practice is carried out in a chromic-sulphuric acid solution. In this work, investigations are carried out aiming to replace the harmful high chromium solution with an environmentally friendly one. A suitable environmentally friendly etching solution is proposed, with an optimal composition of the solution and working conditions. It can be used in the pretreatment of the ABS substrate for the subsequent deposition of copper or nickel coatings from the corresponding solutions with and without a reducer.

Wireless Power Transfer Utilizing a High-$Q$ Self-Resonant Structure

The range and efficiency of a wireless power transfer (WPT) system is limited by the quality factor of the resonant coils. Conventional resonant coils are made from solid or Litz wire. At megahertz frequencies solid wire is not utilized well due to skin effect, and Litz wire is very lossy due to proximity effect. We present a multilayer self-resonant structure as a low-cost method for creating high- $Q$ coils. This structure uses thin foil layers that are separated by a dielectric material in order to form an LC resonator, while also forcing equal current sharing between conductors. The self-resonant structure makes it feasible to achieve advantages similar to Litz wire, but at multi-megahertz frequencies where effective Litz wire is not commercially available. These structures are made with foil layers much thinner than a skin depth, which can make handling these thin layers a challenge. To solve this problem, we also present a modified self-resonant structure in which the layered conductors are made with flex-PCB substrates with no vias. The PCB substrates provide a relatively inexpensive way to handle thin conductive layers, and the modified self-resonant structure ensures that the poor dielectric properties of the PCB substrates do not impact the quality factor of the structure. A prototype of the modified self-resonant structure has a quality factor of 1183 at 7.09 MHz, despite only being 6.6 cm in diameter, which is more than 6.5x larger than other coils presented in the literature with a similar diameter. An experimental WPT setup utilizing two self-resonant structures achieves 94 $\%$ efficiency at a distance of 5.0 cm, which is more than twice the distance as similarly sized conventional coils can achieve while maintaining the same efficiency.

A low temperature co-fired ceramic power inductor manufactured using a glass-free ternary composite material system

A glass-free ternary composite material system (CMS) manufactured employing the low temperature (890 °C) co-fired ceramic (LTCC) technique is reported. This ternary CMS consists of silver, NiCuZn ferrite, and Zn2SiO4 ceramic. The reported device fabricated from this ternary CMS is a power inductor with a nominal inductance of 1.0 μH. Three major highlights were achieved from the device and the material study. First, unlike most other LTCC methods, no glass is required to be added in either of the dielectric materials in order to co-fire the NiCuZn ferrite, Zn2SiO4 ceramic, and silver. Second, a successfully co-fired silver, NiCuZn, and Zn2SiO4 device can be achieved by optimizing the thermal shrinkage properties of both NiCuZn and Zn2SiO4, so that they have a very similar temperature shrinkage profile. We have also found that strong non-magnetic elemental diffusion occurs during the densification process, which further enhances the success rate of manufacturing co-fired devices. Last but not least, elemental mapping suggests that strong magnetic elemental diffusion between NiCuZn and Zn2SiO4 has been suppressed during the co-firing process. The investigation of electrical performance illustrates that while the ordinary binary CMS based power inductor can deal with 400 mA DC, the ternary CMS based power inductor is able to handle higher DC currents, 700 mA and 620 mA DC, according to both simulation and experiment demonstrations, respectively.

The role of dielectric permittivity in the energy storage performances of ultrahigh-permittivity (SrxBa1−x)(Ti0.85Sn0.15)O3 ceramics

Dielectrics for energy storage devices should commonly achieve the requirement of high permittivity, large breakdown strength, and large polarization when used in harsh working environments. A question is gradually raised about permittivity/polarization/breakdown strength in a dielectric for high voltage applications which one is more conducive to energy storage performances. Here, an attempt has been made to investigate the effect of high permittivity on the energy performances of dielectric materials in order to provide a viable option for high voltage devices. High values of dielectric permittivity (1300–7400) combined with low dielectric loss (< 0.8%) are obtained from single-phase (Sr, Ba)(Ti0.85Sn0.15)O3 ceramics by solid-state sintering method. Although permittivity varies greatly, energy performance is basically limited on the same order of < 1.0J/cm3 if measured at low bias field. An interesting finding is that breakdown strength dominates the energy performances in dielectric materials regardless of the great difference of dielectric permittivity, especially at ultrahigh electric fields.

Measurement comparison among time-domain, FTIR and VNA-based spectrometers in the THz frequency range

In this paper we present the outcome of the first international comparison in the terahertz frequency range among three different kinds of spectrometers. A Fourier-Transform infrared spectrometer, a vector network analyzer and a time-domain spectrometer have been employed for measuring the complex refractive index of three travelling standards made of selected dielectric materials in order to offer a wide enough range of parameters to be measured. The three spectrometers have been compared in terms of measurement capability and uncertainty.

30am2-PN-60 光波長計測のための金属ホールアレイ構造を有するナノメカニカル振動子の作製

A nanomechanical resonator for wavelength detection was proposed. The sub-wavelengh metallic hole array were applied for the nanomechanical resonator in order to generate surface plasmon. Surface plasmon was used for the device son that light absorption rate had the wavelength dependence. Surface plasmon generate on both side of sub-wavelength metallic hole array. In this study, both sides of the sub-wavelengh metallic hole array were covered with same dielectric materials in order to improve the light wavelength sensitivity. We examined the wavelength sensitivity of the device in the region from 1547 to 1563 nm. The wavelength sensitivity of the device which we proposed in this research was 9.13 pm.

超高真空仕様表面波励起高密度プラズマ発生装置の評価

A microwave launcher with a ring slot has been designed, allowing a UHV viewing port to be utilized as a dielectric material in order to induce high-density plasma with the surface wave mode in a UHV compatible chamber. Electrostatic probe measurements on the plasma show that the plasma density distribution results from an intensive ionization rate in the vicinity of the dielectric/plasma interface and from the ambipolar diffusion. When nitrogen is mixed to argon gas, the plasma density remains almost constant as a result of the descrete surface mode, whereas the atomic nitrogen density varies in proportion to the nitrogen partial pressure.

An experimental design study of some S- and X-band helical aerial systems

The general characteristics of helical aerials are summarized and the results of polar-diagram measurements in the S- and X-bands are given for single and multiple helices. Reference is made to methods of widening both the beam width and the bandwidth obtained with a helical aerial by means such as end loading and tapering.The possibility of adapting helical aerials to give wide-band linearly polarized arrays is explored experimentally with a considerable measure of success.Tests show that acceptable characteristics may be obtained with helices of ‘unorthodox’ form or with dimensions outside the limits suggested by Kraus.Encapsulation of helical aerials in foamed dielectric material in order to improve their rigidity is found to be a satisfactory and practical proposition provided that the materials are selected with some care, particularly in the X-band.

A High Voltage Direct Current Generator

This high-voltage direct-current generator supplied with alternating current utilizes a so-called ''''Villard''s chain'''' i.e. a voltage-adding and current-rectifying chain of capacitors and diodes. The capacitor plates are disposed in two parallel spaced rows and the capacitor plates of any pair of successive adjacent capacitors in each line of capacitors are closely adjacent, the diodes being housed in the gap left between the two rows of capacitor plates, the diode and capacitor assembly being embedded in a mass of dielectric material in order to constitute a compact, three-terminal block. Thus, a high-power generator can be constructed will very reduced overall dimensions and weight.