Showing papers on "Insulator (electricity) published in 1998"

Discovery of a useful thin-film dielectric using a composition-spread approach

Abstract: The continuing drive towards miniaturization of electronic devices1 is motivating the search for new materials. Consider, for example, the case of the much-used dynamic random-access memory. The minimum capacitance per cell that can be tolerated is expected2 to remain at 30–40 fF, but as the cell area decreases, the corresponding reduction in geometric capacitance has to be compensated for. So far, this has been achieved by resorting to complex non-planar structures and/or using much thinner films of the dielectric insulator, amorphous silicon dioxide (a-SiOx), although the latter approach is limited by the electric fields that can be supported by a-SiOx before its insulating properties break down. An alternative strategy is to develop thin-film insulators that have a dielectric constant significantly greater than that of a-SiOx, reducing the size of the fields required for device operation. Here we show that a composition-spread technique allows for the efficient evaluating of materials with both a high dielectric constant and a high breakdown field. We apply this approach to the Zr–Sn–Ti–O system, and we find that compositions close to Zr0.15Sn0.3Ti0.55O2−δ are better thin-film dielectrics than high-quality deposited a-SiOx. Although detailed tests of the performance of these materials have not yet been carried out, our initial results suggest that they are likely to be comparable to the best alternatives (such as (Ba, Sr)TiO3) currently being considered for integrated-circuit capacitors.

Multilayer ultra-high gradient insulator technology

Abstract: The authors investigate a novel insulator concept which involves the use of alternating layers of conductors and insulators with periods less than 1 mm. These structures perform many times better (about 1.5 to 4 times higher breakdown electric field) than conventional insulators in long pulse, short pulse and alternating polarity applications. They present their ongoing studies investigating the degradation of the breakdown electric field resulting from surface roughness, the effect of gas pressure and the performance of the insulator structure under bipolar stress. Further, they present their initial modeling studies.

Continuous power/signal conductor and cover for downhole use

Abstract: Conductors are placed in insulator which acts as a spacer/centralizer for the conductors, which are in turn mounted within tubing. The void spaces between the insulator and the tubing inside wall can be filled with a sealing material. Alternatively, the voids around the substantially centralized conductors can be used as flow channels for the transmission of fluid pressure to a remote location, such as downhole. The conductors are protected because they are kept away from the tubing wall and can be further protected by the addition of the sealing material.

Electron emission device and display device using the same

Abstract: An electron emission device exhibits a high electron emission efficiency. The device includes an electron-supply layer of metal or semiconductor, an insulator layer formed on the electron-supply layer, and a thin-film metal electrode formed on the insulator layer. The insulator layer has a film thickness of 50 nm or greater. The electron-supply layer has a silicide layer. When an electric field is applied between the electron-supply layer and the thin-film metal electrode, the electron emission device emits electrons.

Porous silicon oxycarbide integrated circuit insulator

Abstract: An integrated circuit includes at least one porous silicon oxycarbide (SiOC) insulator (140, 305), which provides low dielectric constant (e.g., eR < 2) for minimizing parasitic capacitance. The insulator provides IC isolation, such as between circuit elements (115), between interconnection lines (300, 315), between circuit elements (115) and interconnection lines (300, 315), or as a passivation layer (320) overlying both circuit elements and interconnection lines.

Embedded thermal conductors for semiconductor chips

Abstract: A semiconductor chip structure includes a substrate, at least one thermal conductor embedded within the semiconductor chip structure, the thermal conductor providing electrical insulation and a plurality of devices formed within the structure adjacent to the at least one thermal conductor such that during operation heat produced in the devices is transferred into and through the at least one thermal conductor to reduce an operating temperature of the devices. This structure is particularly useful in silicon-on insulator devices. A method of forming embedded thermal conductors in a semiconductor chip includes the steps of providing a substrate having an oxide layer formed thereon, etching trenches into the oxide layer, depositing diamond to fill the trenches to form thermal conductors contacting the substrate and forming devices and contacts adjacent to the thermal conductors for providing heat flow paths to reduce an operating temperature of the devices.

Individual, embedded capacitors for laminated printed circuit boards

Abstract: A method of fabricating individual, embedded capacitors in multilayer printed circuit boards is disclosed. The method is compatible with standard printed circuit board fabrication. The capacitor fabrication is based on a sequential build-up technology employing a first patternable insulator. After patterning of the insulator, pattern grooves are filled with a high dielectric constant material, typically a polymer/ceramic composite. Capacitance values are defined by the pattern size, thickness and dielectric constant of the composite. Capacitor electrodes and other electrical circuitry can be created either by etching laminated copper, by metal evaporation or by depositing conductive ink.

Vacuum-surface flashover switch with cantilever conductors

Abstract: A dielectric-wall linear accelerator is improved by a high-voltage, fast rise-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface.

Adjustable electrode and related method

Abstract: The present invention relates to a electrode assembly and related method that includes a insulator assembly, an electrode assembly, a charging system, a mechanism for measuring electrical voltages, a mechanism for adjusting the distance between inner and outer electrode tips, and a controller. The insulator assembly includes an insulator body having a hollow central portion with a threaded inner wall. The insulator assembly includes inner and outer conductors that are electrically connected to the charging system and are physically connected to inner and outer electrodes, respectively. The electrodes are positioned such that their longitudinal axes are aligned and the tips of the electrodes are in relatively close physical proximity. The distance between the tips is defined as the spark gap. The charging system charges a capacitor that discharges and forms a spark across the spark gap. The electrical measuring mechanism measures the discharge voltage of the capacitor and the controller compares it to a reference voltage, issuing a correction signal to the adjusting mechanism that repositions the electrodes, thus optimizing the spark gap. An alternate embodiment analyzes the charge and discharge characteristics of an electrode assembly that utilizes a second capacitor and an inductor to adjust the spark gap.

The Quantized Hall Insulator: A New Insulator in Two-Dimensions

Abstract: Quite generally, an insulator is theoretically defined by a vanishing conductivity tensor at the absolute zero of temperature. In classical insulators, such as band insulators, vanishing conductivities lead to diverging resistivities. In other insulators, in particular when a high magnetic field (B) is added, it is possible that while the magneto-resistance diverges, the Hall resistance remains finite, which is known as a Hall insulator. In this letter we demonstrate experimentally the existence of another, more exotic, insulator. This insulator, which terminates the quantum Hall effect series in a two-dimensional electron system, is characterized by a Hall resistance which is approximately quantized in the quantum unit of resistance h/e^2. This insulator is termed a quantized Hall insulator. In addition we show that for the same sample, the insulating state preceding the QHE series, at low-B, is of the HI kind.

Outdoor high voltage polymeric insulators

Abstract: Composite polymeric insulators are increasingly being accepted by the traditionally cautious electric utilities worldwide. They currently represent about 70% of installed new high voltage insulators in North America. The tremendous growth in the applications of non-ceramic insulators is due to their advantages over the traditional ceramic and glass insulators. However, because polymeric insulators are relatively new the expected lifetime is not known and is of critical interest to the users. In this paper a review is presented of the recent performance experience of high voltage composite polymeric insulators in outdoor service, testing methods, the ranking of the materials, the 'role' of the fillers, the role of the low molecular weight components present in the most widely used insulator types, the mechanisms responsible for the loss and recovery of one of the most important properties of polymers (the hydrophobicity), various methods to optimize the electrical performance and a relatively new method for evaluating polymeric systems in the field.

Electron emission device and display using the same

Abstract: An electron emission device exhibits a high electron emission efficiency. The device comprises an electron supply layer of metal or semiconductor, an insulator layer formed on the electron supply layer, and a thin-film metal electrode formed on the insulator layer. The electron emission device emits electrons when an electric field is applied between the electron supply layer and the thin-film metal electrode. The insulator layer is a dielectric layer having a thickness of 50 nanometers or more, and formed by a vacuum evaporation process with a layer forming rate of 0.5 to 100 nanometers/minute.

Electrostatic holding apparatus and method of producing the same

Abstract: There is disclosed an electrostatic holding apparatus in which a voltage is applied to an electrode formed of a conductive layer disposed on an insulator layer and covered with an insulating dielectric layer in order to cause the insulating dielectric layer to electrostatically attract an object. The electrostatic holding apparatus is formed of a sintered body in which a thermal expansion mitigating layer is disposed between the insulating dielectric layer and the conductive layer and/or between the conductive layer and the insulator layer. The insulating dielectric layer, the conductive layer, the insulator layer, and the thermal expansion mitigating layer are superposed and press-formed in an unfired state to obtain a green body, which is then sintered to obtain the sintered body. An insulating dielectric layer, a conductive layer and an insulator layer are united while differences in coefficient of thermal expansion among these layers are minimized in order to prevent generation of inter-layer delamination, cracks, and the like, and in order to prevent generation of distortion or warping on the electrostatic attraction surface to thereby increase the electrostatic attraction force. Further, the electrostatic holding apparatus has an excellent capability of allowing removal of an object at the time of stopping application of voltage and an increased withstand voltage.

Electron emission device and display device for emitting electrons in response to an applied electric field using the electron emission device

Abstract: An electron emission device exhibits a high electron emission efficiency. The device includes an electron supply layer of metal or semiconductor, an insulator layer formed on the electron supply layer, and a thin-film metal electrode formed on the insulator layer. The insulator layer is made of a polycrystal dielectric substance and has a film thickness of 50 nm or greater and has a polycrystal phase with an average grain size of 5 to 100 nm as a major component and an amorphous phase as a minor component. When an electric field is applied between the electron supply layer and the thin-film metal electrode, the electron emission device emits electrons.

Study of precursor gases for focused ion beam insulator deposition

Abstract: The electrical properties of insulators formed by focused ion beam induced deposition of various siloxane precursor gases have been compared. Leakage current and breakdown field have been measured by forming metal-insulator-metal structures. It was found that the focused ion beam induced deposition of metal on top of the insulator can substantially degrade the quality of the insulator. We found that the resistivity of the insulator material depends on the deposition yield (e.g., the amount of Ga implantation) as well as on the chemical nature of the precursor gas. From the precursor gases studied, the new compound pentamethylcyclopentasiloxane shows the best performance. Compared to the commercially used tetramethylcyclotetrasiloxane compound, an improvement in resistivity by two orders of magnitude (∼8×1011 versus ∼6×109 Ω cm) and a factor of about 1.5 in breakdown field (650 vs 440 V/μm) could be achieved.

Package for a semiconductor device

Abstract: A package for a semiconductor substrate capable of being fabricated with a desirable heat radiation capability. The package includes a laminate metal substrate consisting of a metal plate, an insulator provided on the metal plate, and copper foil provided on the insulator. The metal plate is patterned to form heat spreaders/ground planes and a plurality of solitary land patterns electrically insulated from each other. The copper foil forms wings and an island pattern. The wirings and island pattern are respectively electrically connected to the land patterns and heat spreaders/ground planes by via holes and heat radiation via holes. When the island pattern is provided with ground potential, the heat spreaders/ground planes are also provided with ground potential. At the same time, the heat spreaders/ground planes efficiently release heat output from the rear of an LSI (Large Scaled Integrated Circuit) to the outside of the package.

Shallow trench isolation technology to eliminate a kink effect

Abstract: A process for creating an insulator filled, shallow trench, in a semiconductor substrate, in which the insulator layer in the shallow trench, is not exposed to procedures used to remove defining composite insulator layers, has been developed. The process features creating a lateral recess, in a thick silicon nitride layer, used as a component of a composite insulator layer, where the composite insulator layer is used for subsequent definition of the shallow trench, in the semiconductor substrate. An insulator deposition, filling openings, and recesses, in the composite insulator layer, and filling the shallow trench, followed by removal of excess insulator fill, on the top surface of the composite insulator layer, results in the formation of a "T" shape insulator, comprised of an insulator shape, in the shallow trench, and comprised of a wider insulator shape, located in the composite insulator shape, with the lateral recess in the thick silicon nitride layer, and with the wider insulator shape, overlying the narrow, insulator shape, in the shallow trench. The insulator, in the shallow trench, is protected from the procedure used to remove components of the composite insulator layer, by the wider insulator shape.

A field emitter device with a current limiter structure

Abstract: A field emitter device includes a column conductor (22), an insulator (23), and a resistor structure (32) for advantageously limiting current in a field emitter array. A wide column conductor (22) is deposited on an insulating substrate (21). An insulator (47) is laid over the column conductor (22). A high resistance layer (32) is placed on the insulator (23) and is physically isolated from the column conductor (22). The high resistance material may be chromium oxide or 10-50 wt.% Cr+SiO. A group of microtip electron emitters (30) is placed over the high resistance layer (32) to connect in an electrical series circuit the colum conductor (22), the high resistance layer (32), and the group of electron emitters (30). One or more layers of insulator (23) and a gate electrode (24), all with cavities for the electron emitters, are laid over the high resistance material (32). One layer of insulator is selected from a group of materials including SiC, SiO, and Si3N4. An anode plate (60) is attached with intermediate space (70) between the anode plate (60) and the microtip electron emitters (30) being evacuated.

Electron emission device with electron supply layer of hydrogenated amorphous silicon

Abstract: An electron emission device exhibits a high electron emission efficiency. The device includes an electron-supply layer of metal or semiconductor, an insulator layer formed on the electron-supply layer, and a thin-film metal electrode formed on the insulator layer. The insulator layer has a film thickness of 50 nm or greater. The electron-supply layer is made of hydrogenated amorphous silicon. When an electric field is applied between the electron-supply layer and the thin-film metal electrode, the electron emission device emits electrons.

Characteristics of Metal/Ferroelectric/Insulator/Semiconductor Field Efffect Transistors Using a Pt/SrBi_2Ta_2O_9/Y_2O_3/Si Structure

Abstract: For the fabrication of metal/ferroelectric/insulator/semiconductor field effect transistors (MEFISFETs), SrBi2Ta2O9 (SBT) film was formed onto Y2O3 layer using the metal organic deposition (MOD) method. Memory windows of MEFISFET were in the range of 0.96–1.38 V when the gate voltage varied from 5 to 7 V. Current-voltage characteristic and transconductance curve of the MEFISFET show the effective gate modulation and the stable memory effect induced by the ferroelectric properties.

Multi-electrode electrostatic chuck having fuses in hollow cavities

Abstract: A failure resistant electrostatic chuck 20 for holding a substrate 35 during processing of the substrate 35 comprises one or more electrodes 25 covered by an insulator 30, the electrodes 25 capable of electrostatically holding a substrate 35 when a voltage is applied thereto. An electrical power bus 40 comprises one or more output terminals 45 that conduct voltage to the electrodes 25. The fuses 50 are positioned in hollow cavities 55 in the insulator 30, and electrically connect the electrodes 25 in series to the output terminals 45 of the power bus 40. Each fuse 50 can electrically disconnect an electrode 25 from an output terminal 45 when the insulator 30 covering the electrode 25 punctures and exposes the electrode 25 to a plasma process environment thereby causing a plasma current discharge to flow through the fuse 50.

The use of insulated time-domain reflectometry sensors to measure water content in highly saline soils

Abstract: In a conducting medium, the energy of a time-domain reflectometry (TDR) pulse is dissipated and the signal is attenuated. Above a certain high conductivity, however, the signal is completely attenuated and the soil short-circuits the sensor. This behaviour of the signal with conductivity severely limits the TDR technique in measuring water content in highly saline soils. By reducing the direct contact between the conductive soil and the metallic sensor the energy of the pulse is better maintained. Different combinations were tried: we insulated the central wire, outer two wires, and all wires of a three-wire sensor with two different insulators. The first insulator was an adhesive polyethylene sheet usually used as a transparent cover and the second insulator was an adhesive tape. The insulated sensors were used to measure dielectric constants in non-saline soils and water and in saline soils. The sensors with the insulated centre wire preserve maximum energy and maintain a clear signal in saline soils. The insulating materials have very small dielectric constants. The TDR exerts a larger influence in the vicinity of the wires of the sensor during measurements. Therefore, the insulated sensor measures a dielectric constant which is smaller than the apparent dielectric constant of the surrounding medium. The type of insulating material also has an effect on the dielectric constant. Therefore, it is necessary to calibrate the sensors for the specific insulator.

Thermal conductance of IC interconnects embedded in dielectrics

Abstract: Accurate prediction of temperatures in metal wiring for integrated circuits is essential to the evaluation of electromigration reliability for high-frequency applications and electrical overload as well as for wafer-level die testing. Accurate prediction requires knowledge of the thermal conductivity of the surrounding dielectric and the heating effect of applied currents. Both quasi-analytical and numerical models for line heating as a function of applied current are presented for the case of lines fully embedded in a dielectric. Heat loss and current density at the melting point are projected as a function of linewidth, line thickness, underlying insulator thickness and insulator thermal conductivity. As intuitively expected, these projections indicate the allowed current density decreases with increasing linewidth, line thickness and insulator thickness, and also decreases as thermal conductivity decreases. Furthermore, the models are found to match heat loss measurements for isolated lines in SiO/sub 2/ and return a value of 1.07 W/m-/spl deg/K for the thermal conductivity of the oxide.

Method for improving performance of highly stressed electrical insulating structures

Abstract: Removing the electrical field from the internal volume of high-voltage structures; e.g., bushings, connectors, capacitors, and cables. The electrical field is removed from inherently weak regions of the interconnect, such as between the center conductor and the solid dielectric, and places it in the primary insulation. This is accomplished by providing a conductive surface on the inside surface of the principal solid dielectric insulator surrounding the center conductor and connects the center conductor to this conductive surface. The advantage of removing the electric fields from the weaker dielectric region to a stronger area improves reliability, increases component life and operating levels, reduces noise and losses, and allows for a smaller compact design. This electric field control approach is currently possible on many existing products at a modest cost. Several techniques are available to provide the level of electric field control needed. Choosing the optimum technique depends on material, size, and surface accessibility. The simplest deposition method uses a standard electroless plating technique, but other metalization techniques include vapor and energetic deposition, plasma spraying, conductive painting, and other controlled coating methods.

The breakdown electric field between two conducting spheres by the method of images

Abstract: The determination of the breakdown electric field of air between two identical conducting spheres is a good example of the use of the method of images to solve a practical problem in engineering electromagnetics. The sparkover electric field is computed from published or measured data for the breakdown voltage by using the theoretical solution for the image charges. Thus students are exposed to a sophisticated method of images solution involving two sets of infinitely many charges. Additional educational benefits include an enhanced appreciation for the properties of air as an insulator, for the limits of the electroquasistatic approximation, for the numerical convergence properties of infinite series, and for the history of science. Instead of using published tables, an exposure to high-voltage engineering to obtain measured breakthrough data is an option if a suitable laboratory is available.

The influence of surface currents on pattern-dependent charging and notching

Abstract: Surface charge dissipation on insulator surfaces can reduce local charging potentials thereby preventing ion trajectory deflection at the bottom of trenches that leads to lateral sidewall etching (notching). We perform detailed Monte Carlo simulations of pattern-dependent charging during etching in high-density plasmas with the maximum sustainable surface electric field as a parameter. Significant notching occurs for a threshold electric field as low as 0.5 MV/cm or 50 V/µm, which is reasonable for the surface of good insulators. The results support pattern-dependent charging as the leading cause of notching and suggest that the problem will disappear as trench widths are reduced.

Spark plug with specific measured parameters

Abstract: A spark plug has an insulator having a through hole extending in an axial direction thereof and an insulator leg portion at an end thereof, a resistor disposed in the through hole, a central electrode disposed in the through hole to face a central electrode side end face of the resistor and protruding from an insulator end face of the insulator leg portion, and a housing holding the insulator. A length between the insulator end face and the central electrode side end face of the resistor is equal to or larger than 1.5 times as large as a length of the insulator leg portion in the axial direction. Accordingly, temperature at a contact portion between the resistor and the central electrode is prevented from being increased, resulting in long life of the spark plug.

Real-time observation of surface charging on a cylindrical insulator in vacuum

Abstract: By using an electrostatic probe located close to the triple junction on the cathode surface, we have conducted real-time observations of the change in electric field due to surface charging of an insulator in vacuum. A cylindrical sample made of polymethylmethacrylate (PMMA) or Al/sub 2/O/sub 3/ has been exposed to HVDC. An axisymmetric simulation based on the secondary electron emission electron avalanche (SEEA) theory has been performed. The measured results agreed with the simulation concerning the polarity of the accumulated charge as well as the field strength. The simulation also predicts the inception of charging at a voltage well below the measured flashover voltage. These results clearly support the SEEA theory as a macroscopic mechanism of surface charging of an insulator in vacuum.

Simulation of electrical tree growth in solid insulating materials

Abstract: In this paper the electrical tree growth in solid insulating materials is modeled using von Neumann's Cellular Automata (CA). The model is based upon the assumption that the electric stress at the end of a conducting tip quite often approaches the dielectric strength of the material and that progressive breakdown can occur by electrical tree formation. Because of tree advancement, the potential distribution into the insulating material changes with time and is calculated at each time step. An algorithm for the simulation of electrical tree growth in solid dielectrics based on this model has been developed. The algorithm is also used to simulate breakdown in solid dielectrics containing square or spherical voids.