Dielectric Break Research Articles

Influence of molybdenum ions on the structure of ZnO–As 2O 3–Sb 2O 3 glass system by means of spectroscopic and dielectric studies

Glasses of the composition 5 ZnO–(50 − x) As 2O 3–45 Sb 2O 3:x MoO 3, with six values of x ranging from 0 to 10 mol% are prepared. The samples are characterized by X-ray diffraction, scanning electron microscopy and differential thermal analysis (DTA) techniques. A number of studies, viz., spectroscopic properties (optical absorption, IR, Raman, and ESR spectra), magnetic susceptibility and dielectric properties (dielectric constant ε′, loss tan δ, ac conductivity σ ac over a wide range of frequency and temperature as well as dielectric break down strength at room temperature), are carried out as a function of molybdenum ion concentration and analyzed in the light of different oxidation states of molybdenum. The analyses of the results indicate that molybdenum ions mostly exist in Mo 5+ state rather than in Mo 6+ state.

Stability analysis of dielectric elastomer film actuator

Dielectric elastomer (DE) is the most promising electroactive polymer material for smart actuators. When a piece of DE film is sandwiched between two compliant electrodes with a high electric field, due to the electrostatic force between the two electrodes, the film expands in-plane and contracts out-of-plane so that its thickness becomes thinner. The thinner thickness results in a higher electric field which inversely squeezes the film again. When the electric field exceeds the critical value, the dielectric field breaks down and the actuator becomes invalid. An elastic strain energy function with two material constants is used to analyze the stability of the dielectric elastomer actuator based on the nonlinear electromechanical field theory. The result shows that the actuator improves its stability as the ratio k of the material constants increases, which can be applied to design of actuators. Finally, this method is extended to study the stability of dielectric elastomers with elastic strain energy functions containing three and more material constants.

Modeling dielectric charged drop break up using an energy conservation method

In the light of experimental evidence a previously published model to predict the charge and mass redistribution when charged dielectric drops break up has been updated. In particular we have taken the dielectric nature of the liquid, the existence of an external electric field and used photographic evidence of drop break up as a basis for geometrical assumptions that are physically realistic. We have assessed the sensitivity of the charge redistribution assumption and the improved model compares well with the recent accurate experimental evidence. The results apply to ratio of quantities of mass and charge, making the model extremely simple and economical to apply to multi-dimensional charged spray computer codes in order to predict evaporating charged sprays accurately.

C0G 온도계수 특성을 가지는 고압용 적층 칩 캐패시티의 유전 및 내전압 특성

High voltage MLCCs with C0G temperature coefficient characteristics could apply DC-DC invertor were investigated for its dielectric properties. Also we manufactured MLCC through various process and studied the characteristics of dielectric break down voltage [BDV] and dielectric property as the variation of thickness in the green sheet and how to pattern the internal electrode. As the thickness of green sheet is increase, the dielectric BDV per unit thickness is decreased. But as the pattern of internal electrodes were floated we could manufacture the high voltage MLCC maintained its dielectric BDV a unit.

First-principle theoretical study on the electronic properties of SiO 2 models with hydrogenated impurities and charges

We adopt first-principle approach to calculate potential energy surfaces for α-quartz and -cristobalite silicon dioxide (SiO 2) with hydrogenated impurities in the neutral, positive, and negative charged states. It is expected that H atoms in SiO 2 have an important role to generate leakage current paths. In this paper, we calculate stable and unstable positions of a migrating H atom and discuss electrons or holes trapping mechanism. These results clarify that the dynamics of the H atom in the neutral, negative, and positive charged states should be different from one another, and therefore, the mechanism of the dielectric break down of SiO 2 also depends on the charged environment. Based on the regional density functional theory, we have calculated the effective charge tensor density of the migrating H atom in the neutral state.

Porous Silica Xerogel Processing And Integration For Ulsi Applications

ABSTRACTWith a tunable ultra low dielectric constant, porous silica xerogel is an attractive dielectric material for ULSI interconnect applications and is potentially extendable to multiple future technology nodes. Porous silica xerogel films have been processed and integrated into device test structures as ultra low k intermetal dielectrics. A fully automated thin film deposition process is recently developed and gives high throughput and good repeatability. A surface modification technique is used to make the films hydrophobic. The film dielectric constant is measured to be less than 2, depending on porosity. Because of the small pore sizes, the films display high dielectric break down strength. With proper shrinkage control, porous silica xerogel shows excellent gapfill capabilities. Integration of the porous silica xerogel material into CMP planarized double level metal (DLM) test structures with both Al and W plugs in a gapfill scheme is successful. Porous silica xerogel structures provide 14% and 35% total capacitance reduction compared to structures with hydrogen silsesquioxane (HSQ) and high density plasma (HDP) oxide respectively. Reliability and current leakage data of porous silica xerogel are comparable to that of HSQ. Feasibility of integrating porous silica xerogel into Cu damascene structures is also demonstrated. Cu/xerogel damascene structures exhibit improvements in both resistance and capacitance compared with convention Al/Oxide gapfill structures.

Passivation of Zinc in Acid Electrolytes Under Galvanostatic Conditions

AbstractPassivation behaviour of zinc electrodes in 4–10 M H2SO4 and some hydrogensulphates and alkylammonium salts with anions containing S–VI in the concentration range 0.5–5 M were studied under galvanostatic conditions. After a transition time τ, voltage increased steeply, indicating the onset of passivation. The product j · √τ is found to be roughly constant. This is explained in terms of an accumulation of zinc ions in front of the electrode up to the point, where the concentration reaches saturation. From the Sand constant, a diffusion coefficient was calculated in the right order, depending on the electrolyte composition. The passive layer is assumed to be the corresponding zinc salt. Only at 30–100 V, dielectric break down occurs under potentiostatic conditions. Open circuit potential in the passive region attains in short times (ms) the active potential again. From this it is concluded that the thickness of the zinc salt layer must be extremely small.

Materials for vacuum seals and dielectric breaks in near term and commercial reactor designs

Evaluations have been made of currently available sealing materials and concepts and their potential applicability to fusion reactor devices. The environments imposed on seals for fusion reactors are more severe than most applications. Elastomeric, metal, and welded seals were evaluated. Elastomeric materials are not effective for use at radiation dose levels greater than 10 8 rads; the best are polyurethane or ethylene propylene. Welded seals and metal seals offer the advantage of reliability once a seal is made but lack the ease of use inherent in elastomer seals. The sealing of a fusion reactor vacuum chamber is a non-trivial matter and will require R&D on a multitude of design options.

Anodic oxidation and stress corrosion cracking (SCC) of titanium alloys

Uniform and reproducible oxide films were formed on alloy Ti-6Al-6V-2.5Sn by anodic oxidation in aqueous 0.5% H3BO3, at 10 mA cm−2 and voltages up to 110V; dielectric break down occurred above 120V. A parallelism was found between the effect of environmental factors on stress corrosion cracking (SCC), as reported in the literature and the anodic behaviour, as observed by ourselves: factors that increased susceptibility to SCC (increase in temperature or viscosity, alloying, introductions of CI− or methanol, lowering of pH) reduced passivity under anodic polarization, while factors that inhibited SCC (thicker oxide films, high pH, phosphate ions) increased passivity. The passivity was associated both with the presence of the anodic oxide and with a transitory effect of the electric field across the oxide and the oxide-electrolyte interface.

Anodic oxidation and stress corrosion cracking (SCC) of titanium alloys

Uniform and reproducible oxide films were formed on alloy Ti-6AI-6V-2.5Sn by anodic oxidation in aqueous 0.5~ H3BO3, at 10 mA cm -2 and voltages up to 110V; dielectric break down occurred above 120V. A parallelism was found between the effect of environmental factors on stress corrosion cracking (SCC), as reported in the literature and the anodic behaviour, as observed by ourselves: factors that increased susceptibility to SCC (increase in temperature or viscosity, alloying, introductions of CI or methanol, lowering of pH) reduced passivity under anodic polarization, while factors that inhibited SCC (thicker oxide films, high pH, phosphate ions) increased passivity. The passivity was associated both with the presence of the anodic oxide and with a transitory effect of the electric field across the oxide and the oxide-electrolyte interface.

Laser-Triggered Solid Dielectric Switching

A Q-switched ruby laser was used to initiate breakdown in solid dielectric switches with a jitter of less than 3 ns. "Lexan" polycarbonate in thickness from 40 to 80 mils withstood applied voltage pulses (less than 1 μs duration) of up to 400 kV. Laser pulse energy of less than 1 joule was sufficient to initiate breakdown in the solid dielectric. A focusing lens and the switch container were immersed in a grading solution of copper sulfate and water. Command triggering down to 50% of the dielectric's self break voltage was demonstrated. A test system employing a miniature Marx generator, and a high energy system switching 150 kA at 400 kV to form precisely timed relativistic electron beams, are described.