Modeling of high permittivity insulator structure with interface charge by charge compensation

An analytical model of the power metal–oxide–semiconductor field-effect transistor(MOSFET)with high permittivity insulator structure(HKMOS)with interface charge is established based on superposition and developed for optimization by charge compensation.In light of charge compensation,the disturbance aroused by interface charge is efficiently compromised by introducing extra charge for maximizing breakdown voltage(BV)and minimizing specific ON-resistance(R_(on,sp)).From this optimization method,it is very efficient to obtain the design parameters to overcome the difficulty in implementing the R_(on,sp)–BV trade-off for quick design.The analytical results prove that in the HKMOS with positive or negative interface charge at a given length of drift region,the extraction of the parameters is qualitatively and quantitatively optimized for trading off BV and Ron,sp with JFET effect taken into account.

A novel Na_(1−x)K_(x)TaO_(3)perovskite microwave dielectric ceramic with high permittivity and high positive temperature coefficient

A novel Na_(1−x)K_(x)TaO_(3)(x=0,0.025,0.05,0.075,0.1,and 0.15)ceramic with high permittivity and high positive temperature coefficient was synthesized via the conventional solid-state method.All samples were determined to be pure phase orthorhombic NaTaO3 structure of space group Pmcn,and larger grain and lower porosity were observed after adding an appropriate amount of K+ions.The Q×f value is majored by the packing fraction and grain size,while the value ofτf is influenced by Ta–O bond valence.The Na_(0.95)K_(0.05)TaO_(3) ceramic possesses excellent dielectric properties ofεr=164.29,Q×f=9091 GHz(f=3.15 GHz),tanδ=3.46×10^(–4),τf=+809.52 ppm/℃,sintered at 1550℃.Compared with NaTaO_(3) ceramics,the Na_(1−x)K_(x)TaO_(3)ceramics prepared in this study demonstrate higher dielectric constants and higher positive temperature coefficients,which are promising for device miniaturization andτf compensators.

Enhanced radiation characteristics for antipodal Vivaldi antenna using high permittivity dielectric director

In this paper,we investigate the influence of higher permittivity dielectric director on the radiation performances of an antipodal Vivaldi antenna.An elliptical dielectric director with high permittivity is inserted in an antipodal Vivaldi antenna aperture in order to ameliorate the radiation characteristics of the antenna.Due to the capacity of elevated permittivity dielectric to confine and guide energy in the desired direction,an increment of 4 dB in the gain of the antenna is obtained.This antenna,which covers an ultra-wide frequency band of 146.8%from 2.3 GHz to 15 GHz,has approximately regular radiation patterns with reduced side lobe level and narrower beamwidth.In the interest to achieve radar application necessities,the proposed antenna is exploited to develop an antenna array which consists of four connected elements.Adding dielectric directors can significantly enhance the radiations characteristics of the antenna and reduce the mutual coupling inter-elements.So using four elements with dielectric director in the antenna array can achieve the same results obtained with eight elements without directors.This can decrease the used number of elements that form the antenna array.

Wide-Temperature-Range Dielectric Permittivity Measurement under High Pressure

Two measurement systems are developed for in-situ dielectric property measurement under high pressure in a wide-temperature range from 77K to 1273 K. The high-temperature system ranging from room temperature up to 1273K is equipped with a hexahedron anvils press, while the low-temperature system ranging from liquid nitrogen temperature to normal condition is equipped using the piston cylinder setup with a specially designed sample chamber. Using these configurations, the dielectric property measurement of ferroelectrie BaTiO3 and multiferroie Tm0.5Gd0.5MnO3 compounds are demonstrated, which proves the validity of the systems through the tuning of the polarization and phase transition boundary by high pressure. These two systems will be equally applicable to a wide variety of electronic and transport property measurements of insulators, semiconductors, as well as battery materials.

Ultra-low specific on-resistance vertical double-diffused metal-oxide semiconductor with a high-k dielectric-filled extended trench

An ultra-low specific on-resistance trench gate vertical double-diffused metal-oxide semiconductor with a high-k dielectric-filled extended trench（HK TG VDMOS） is proposed in this paper.The HK TG VDMOS features a high-k（HK） trench below the trench gate.Firstly,the extended HK trench not only causes an assistant depletion of the n-drift region,but also optimizes the electric field,which therefore reduces Ron,sp and increases the breakdown voltage（BV）.Secondly,the extended HK trench weakens the sensitivity of BV to the n-drift doping concentration.Thirdly,compared with the superjunction（SJ） vertical double-diffused metal-oxide semiconductor（VDMOS）,the new device is simplified in fabrication by etching and filling the extended trench.The HK TG VDMOS with BV = 172 V and Ron,sp = 0.85 mΩ·cm2 is obtained by simulation;its Ron,sp is reduced by 67% and 40% and its BV is increased by about 15% and 5%,in comparison with those of the conventional trench gate VDMOS（TG VDMOS） and conventional superjunction trench gate VDMOS（SJ TG CDMOS）.

High Index SMES Device for Gravitomagnetic Field Generation

A method is described for creating a measurable unbalanced gravitational acceleration using a gravitomagnetic field surrounding a superconducting toroid as described by Forward (1962). An experimental Superconducting Magnetic Energy Storage (SMES) toroid configuration of wound superconducting nanowire is proposed to create a measurable acceleration field along the axis of symmetry, providing experimental confirmation of the additive nature of a Lense-Thirring derived gravitomagnetic field. In the present paper, gravitational coupling enhancement of this effect is explored using a high index or high permittivity material, as predicted by Sarfatti (2020) using his modification to Einstein’s General Relativity Field Equations for gravitational coupling in matter.

Greatly enhanced permittivity in BaTiO_(3)-epoxy dielectric composites with improved connectivity of ceramic phase

BaTiO_(3)-epoxy dielectric composites were prepared by curing the liquid epoxy monomer that infiltrated into the partially-sintered BaTiO_(3)porous ceramics.The BaTiO_(3)volume fraction of the composites maintained around 58.6%with increasing the sintering temperature from 600℃to 1000°C,while the significant microstructure evolution,improved connectivity of BaTiO_(3)phase and dramatical increase in permittivity from 102 to 697 were observed.The permittivity and BaTiO_(3)volume fraction further increased to 2328 and 83.5%for the sintering temperature of 1250℃.The present composites had the permittivity 102 orders of magnitude higher than the 0-3 type ones,and the extraordinary results were mainly attributed to the improved connectivity of BaTiO_(3)phase that benefited from partial sintering.The connectivity also had a significant effect on the temperature dependence of permittivity,and good combination of temperature-stable high permittivity,low dielectric loss and relatively low ceramic fraction could be obtained by regulating the connectivity of BaTiO_(3)ceramic phase.

Effect of carbon-doping on structural and dielectric properties of zinc oxide

In this paper,Carbon-doped Zinc Oxide(C-ZnO)samples were prepared using the solid-state reaction method.The influence of carbon-doping on the structural and dielectric properties of ZnO samples was studied.The shift in the highest peak position(101)in XRD patterns of carbon-doped samples was observed.The Raman peak at 581 cm^(-1) in undoped ZnO was shifted and broadened in carbon-doped ZnO samples.The ZnO samples doped with carbon show higher values of dielectric constant(~2400 at 1 kHz)compared to pure ZnO(~9 at 1 kHz)which was due to increase in native point defects in the samples.The ac conductivity(σ_(ac))value of the carbon-doped sample was enhanced by 103 times for((ZnO)_(0.9) C_(0.1))sample.