Showing papers on "Film capacitor published in 1994"

The fundamentals of aging in HV polymer-film capacitors

Abstract: This paper covers the basic phenomena involved in the aging of capacitors constructed using polymer films as the major dielectric material. A wide variety of aging phenomena can be identified, ranging from simple electrical, dielectric, thermal, radiation, chemical and physical aging, to aging originating from the specific construction of the capacitor. Some phenomena occur quickly, such as some morphological changes in the polymer, others occur progressively, and others occur later in the life of the capacitor. The polymers covered range from biaxially-oriented polypropylene, which is widely used in commercial utility and industrial capacitors, to polymers like polycarbonate, polysulfone, polyimide, and polyvinylidene fluoride, which are used in high-energy density, outer-space, high-temperature, or other special applications. The paper addresses two constructions of polymer film capacitor where the aging phenomena are significantly different due to the differences in construction: polymer/foil capacitors and metalized film capacitors. Metalized polymer film capacitors have the quality of clearing or self healing that is not present in film/foil capacitors. The discussion of aging in this paper is given from the perspective of these two designs. >

Hybrid metal/metal oxide electrodes for ferroelectric capacitors

Abstract: Ferroelectric capacitors with hybrid electrodes including both a conducting oxide and a noble metal may be used to achieve devices having improved performance over capacitors with either platinum or ruthenium oxide electrodes. These hybrid electrode structures can improve capacitor performance both in terms of fatigue and leakage current. Accordingly, these ferroelectric capacitors with hybrid electrodes can be used as elements of an integrated circuit such as a non-volatile memory or dynamic random access memory.

Semiconductor device having a capacitor with an adhesion layer

Abstract: In a semiconductor device and a method of manufacturing the same, adhesion between a capacitor dielectric film made of material having a high dielectric constant and an interlayer insulating film located thereunder is improved, and a leak current from a capacitor lower electrode is effectively prevented. In the semiconductor device, an adhesion layer (11) made of TiO 2 , ZrO 2 , Ta 2 O 5 , Si 3 N 4 or Al 2 O 3 is interposed between the interlayer insulating film made of a silicon oxide film and the capacitor dielectric film made of material having a high dielectric constant. The adhesion layer improves adhesion between the interlayer insulating film and the capacitor dielectric film.

Nanocrystalline layer thin film capacitors

Abstract: The invention relates to a method for forming a high capacitance thin film capacitor comprising forming layers of dielectric material in amorphous, nanocrystalline and polycrystalline configuration and arranging the resulting layers between upper and lower electrodes. The invention further comprises dielectric articles such as capacitors formed in accordance with the method of the invention and includes their use in an electronic circuit.

Semiconductor memory device with high dielectric capacitor structure

Abstract: Transfer gate transistors are formed on a main surface of a semiconductor substrate. The transfer gate transistors have impurity regions for serving as source/drain regions. A first interlayer insulating film having a substantially flat upper surface is formed to cover the transfer gate transistors. The first interlayer insulating film is provided with contact holes reaching the impurity regions. Plugs are formed in the contact holes. Capacitors are only formed on the flat upper surface of the first interlayer insulating film. Lower electrodes of the capacitors and the plugs are electrically connected with each other through barrier layers. Thus, it is possible to improve capacitances of capacitors in a DRAM.

Method for manfacturing a capacitor for a semiconductor memory device having a tautalum oxide film

Abstract: A capacitor for a semiconductor memory device employs a tantalum pentoxide film as a dielectric film. The dielectric film is made from tantalum pentoxide film doped with silicon over a first electrode. A second electrode is then formed over the dielectric film. Accordingly, in the method for manufacturing the device, although the dielectric constant of the dielectric film is somewhat lower than the conventional pure tantalum pentoxide film due to the silicon doped within the tantalum pentoxide film, leakage current is reduced and breakdown voltage is increased. Therefore, the dielectric film according to the present invention exhibits excellent electrical characteristics and high reliability.

Effect of ultraviolet light on fatigue of lead zirconate titanate thin-film capacitors

Abstract: Fatigue of Pb(Zr0.52Ti0.48)O3 (PZT) thin‐film capacitors was studied under UV light (He‐Cd laser, λ=325 nm). The remanent polarization of the PZT film capacitors increased upon light illumination. Fatigue resistance was also improved under UV light. During fatigue test, the change in polarization of PZT films upon UV light illumination increased gradually with cycling. These results were examined within the framework of the polarization screening model, which is suggested as an essential process for fatigue. This leads to a conclusion that more charged defects are involved in the fatigue process through internal screening of polarization.

Capacitors and interconnect lines for use with integrated circuits

Abstract: A multi-region material structure and process for forming capacitors and interconnect lines for use with integrated circuits provides (1) capacitor first or bottom electrodes comprising a transition-metal nitride; (2) a capacitor dielectric comprising a transition-metal oxide; (3) capacitor second or top electrodes comprising a transition-metal nitride, a metal or multiple conductive layers; (4) one or more levels of interconnect lines; (5) electrical insulation between adjacent regions as required by the application; and (6) bonding between two regions when such bonding is required to achieve strong region-to-region adhesion or to achieve a region-to-region interface that has a low density of electrical defects. The process for forming the material structures involves formation of the capacitor dielectric on the first electrode surfaces by conversion of a conductive transition-metal nitride to an insulating transition-metal oxide and formation of low-defect-density interfaces between capacitor second electrodes and the capacitor dielectric.

Method for adjusting sensitivity of a sensor

Abstract: An accelerometer comprising a microfabricated acceleration sensor and monolithically fabricated signal conditioning circuitry. The sensor comprises a differential capacitor arrangement formed by a pair of capacitors. Each capacitor has two electrodes, one of which it shares electrically in common with the other capacitor. One of the electrodes (e.g., the common electrode) is movable and one of the electrodes is stationary in response to applied acceleration. The electrodes are all formed of polysilicon members suspended above a silicon substrate. Each of the capacitors is formed of a plurality of pairs of electrode segments electrically connected in parallel and, in the case of the movable electrodes, mechanically connected to move in unison. When the substrate is accelerated, the movable electrodes move such that the capacitance of one of the capacitors increases, while that of the other capacitor decreases. The two capacitors are connected to signal conditioning circuitry which converts this differential capacitance into a corresponding voltage. Both open loop and force-balance operation are shown. A full scale sensitivity is set based on a preliminary sensitivity calculation.

Electrical components such as capacitors having electrodes with an insulating edge

Abstract: A marginless electrical component, such as a capacitor, is fabricated by providing a multilayer body of electrodes and dielectric with an insulating layer on alternate electrodes on each terminated surface.

Method of making an ultra thin dielectric for electronic devices

Abstract: High quality, ultra thin (<30 Å) SiO 2 /Si 3 N 4 (ON) dielectric layers have been fabricated by in situ multiprocessing and low pressure rapid-thermal N 2 O-reoxidation (LRTNO) of Si 3 N 4 films. Si 3 N 4 film was deposited on the RTN-treated polysilicon by rapid-thermal chemical vapor deposition (RT-CVD) using SiH 4 and NH 3 , followed by in situ low pressure rapid-thermal reoxidation in N 2 O (LRTNO) or in O 2 (LRTO) ambient. Results show that ultra thin (T ox ,eq =˜29Å) ON stacked film capacitors with LRTNO have excellent electrical properties and reliability.

Si LSI Process Technology for Integrating Ferroelectric Capacitors

Abstract: The fabrication procedure of ferroelectric thin film capacitors onto conventional Si LSIs is investigated. Electrical characteristics of the integrated Ba1-x Srx TiO3 (BST) capacitors and the metal-oxide-semiconductor transistors embedded in the Si substrate are examined. Results of these measurements suggest the usefulness of this integration process for the fabrication of ferroelectric thin film devices, which is substantiated by the evaluation of an analog/digital IC with the integrated BST bypass capacitor.

Method for screening early failure of ceramic capacitor

Abstract: A method of screening ceramic capacitors. The method includes the steps of: charging the ceramic capacitors by applying a constant d.c. voltage which is larger than the rated voltage and smaller than the breakdown voltage; and leaving the charged ceramic capacitor in a temperature around the maximum working temperature for a specific period of time with both terminals of each ceramic capacitor opened electrically; and eliminating defective capacitors whose residual voltage values are smaller than a specific voltage value.

Metallized film for electrical capacitors having a semiconductive layer extending entirely across the unmetallized margin

Abstract: A film capacitor in which the unmetallized margin is provided with a semiconductive layer. The layer provides a parallel resistive path within the capacitor, itself, obviating the need for an external resistor. It also grades the electric field across the margin, i.e., makes the field more uniform, thus allowing the margin to be made narrower without electrical breakdown, permitting a reduction in the physical size of the capacitor. A refractory, semiconductive layer is provided between the metal layer and the dielectric film. The refractory layer accelerates the self-clearing process, by insulating the underlying dielectric film from the heat generated by the vaporizing metal, thus hastening vaporization and reducing the tendency of the dielectric film to carbonize. As a result, faults are cleared with substantially less energy consumption. Preferably, the refractory layer is also semiconductive, to reduce field emission effects, and thereby decrease the frequency of faults in the dielectric film.

Implantable cardioverter defibrillator employing polymer thin film capacitors

Abstract: An implantable cardioverter defibrillator (ICD) system employs polymer film capacitor technology for the capacitor system. Unlike existing ICD systems which utilize electrolytic capacitors, the ICD system of the present invention utilizes polymer thin film capacitors to deliver an electrical countershock having an effective pulse duration of greater than the chronaxie duration of the human heart from a maximum stored energy of less than about 35 joules when charged to a maximum charging voltage of at least about 800 volts. Preferably, the polymer thin film capacitors having a dielectric thickness of between about 1,000 nm and 10,000 nm and an effective capacitance of the less than about 80 μF with a maximum charging voltage of less than about 1500 volts or a maximum peak current of less than about 30 amperes.

Active discharge circuit for charged capacitors

Abstract: An active discharge circuit provides for the discharge of filter capacitors in a power supply in the absence of a.c. line power. A detector provides a signal responsive to the removal of the pulsating d.c. charging voltage from the capacitors and a switch responsive to the detector signal closes, coupling an energy dissipating element, in the form of a resistor or a transistor, across the filter capacitor to dissipate its stored energy.

Method for making metallized capacitor having increased dielectric breakdown voltage

Abstract: A metallized film capacitor in which the metallization is made as thin as possible in order to increase the dielectric strength of the film. In the industry, typical metallization thicknesses range from approximately 1-4 ohms/sq, however, the present invention employs thicknesses which range from 5-300 ohms/sq. And, depending on which thickness is used, the effective dielectric strength of the film can be substantially increased. Additionally, the capacitor or various components thereof are exposed to a gas plasma for further increasing the dielectric breakdown voltage.

Modelling and simulation of integral decoupling capacitors in single and multichip module electronics packaging

Abstract: In high-end packaging structures, switching currents of short pulse width and high clock rate generate significant Delta-I noise which can cause malfunctions of IC circuits. The trend of increasing packing density makes the integral decoupling capacitor preferable than the conventional discrete capacitor. Although integral decoupling capacitors have been proposed and already used in some packaging structures, their electrical performance has not been accurately modeled. This paper presents an efficient and accurate numerical technique for the simulation of Delta-I noise in multi-layer power and ground plane packaging structures containing integral decoupling capacitors. Various factors that determine the effectiveness of integral decoupling capacitors, such as their geometries and locations in packaging structures, are also studied. >

Frequency domain (1kHz-40GHz) characterisation of thin films for multichip module packaging technology

Abstract: Parallel plate capacitors for the broadband dielectric characterisation of both high (amorphous BaTiO3 and amorphous TaOx) and low (parylene) dielectric constant thin films were fabricated at low temperature (< 200 °C). The dielectric constant and loss tangent were dermined through the measurement of C, G and the S parameters of the capacitors. These thin film dielectrics exhibit no dispersion in the frequency range 1 kHz – 40 GHz.

Study on Multilayered Electrodes for Ferroelectric Thin Film Capacitors

Abstract: The ferroelectric properties of PZT on RuO2 electrodes were compared to those on RuOStudy on Multilayered Electrodes for Ferroelectric Thin Film Capacitors. It seems that the microstructure of PZT film plays an important role in the improvement of electrical properties. In particular, the change in the grain size of PZT film is responsible for the enhancement of the electrical properties. It was found in this study that films with smaller grain size had larger coercive fields. The exact dependence of the grain size on the hysteretic property is not fully understood at present. However, it is believed that the grain size affects both domain formation and domain pinning because of the influence of grain boundaries. The change in physical properties of PZT films due to the bottom electrode is understood in terms of interfacial modifications. Here we report on a method to modify physical properties of PZT films utilizing interfacial engineering.

Influence of Electrode Contacts on Leakage Current of SrTiO3 Capacitors.

Abstract: The current-voltage (I-V) characteristics of capacitors using SrTiO3 film were investigated. Rectification characteristics were observed, either when oxygen gas was introduced during sputter deposition of top electrodes, or when the SrTiO3 film was annealed in oxygen. These I-V characteristics are attributed to blocking contacts between SrTiO3 and the electrodes. It is considered that such contacts are formed because of the reduction of the crystal defects in SrTiO3 films, and they have decisive influence on the leakage current of the capacitor.

Dc-dc converter and computer using it

Abstract: PURPOSE:To reduce a switching loss by a method wherein, when a switching element is turned off, a snubber capacitor is connected in parallel with the switching element and a capacitor is connected in series with the snubber capacitor in such a way that individual electrodes are of an additive polarity. CONSTITUTION:Single-chip forward converters 34-1, 34-2 which supply electric power to a load 33 from a transformer are connected to capacitors 4-1, 4-2. Then, in the converters 34-1, 34-2, snubber capacitors 5-1,to 5-4 are connected in parallel with the switching elements 5-1 to 5-4 when the switching elements 5-1 to 5-4 are turned off, and the capacitors 4-1, 4-2 are connected in series with the snubber capacitors 7-1, 7-2 in such a way that individual electrodes are of an additive polarity. Thereby, it is possible to obtain the DC-DC converter whose switching loss is reduced, whose overlap period on the secondary side of the transformer is shortened, whose dead time for prevention of the short circuit of a power supply is reduced, whose high frequency is realized and which can be miniaturized.

Power converter having dc filter capacitor

Abstract: PURPOSE:To reduce the size and weight and to increase the safety by making a DC filter capacitor out of a metalized film having segment fuse mechanisms which specifies the width and potential gradient at the rated voltage of the capacitor. CONSTITUTION:Metal deposited on a film 14 constitutes a large number of segments 16 surrounded by a large number of slits 17, and constitutes fuse mechanisms 18 interposed by slits 17 between segments adjoining each other. And oil-impregneted film capacitors are manufactured using metalized films with segment mechanisms this occasion, the potential gradient of the films at the rated voltage of the capacitors is made to be 150V/mum or larger. Besides, the width W of the fuse mechanism 18 sections is in a range of 0.5-1.4mm. Consequently, it becomes possible to reduce the outside dimensions and the weight of capacitors sharply. Besides, it also becomes possible to increase the safety.

Failure analysis of miniaturized multilayer ceramic capacitors in surface mount printed circuit board assemblies

Abstract: New failure analysis results of miniaturized multilayer ceramic capacitors (sizes 0402, 0603, 0805 and 1206) which have been subjected to various degrees of thermal shock up to 450°C by ice-water or dry ice quenching are reported. The thermal shock resistance of 0402 multilayer ceramic capacitors was found to be about 400°C and considerably better than those of the larger ones. Microstructural and layer-by-layer insulation resistance analyses have clearly identified the physical locations responsible for the electrical leakage of defective capacitors. Further, no evidence of silver migration as a dominant failure mechanism has been observed for any of the defective capacitors under usual operating stresses. Comparisons ofI–V characteristics for multilayer ceramic capacitors quenched by ice-water and dry ice confirm that water plays a significant role in causing electrical failure at nominal bias. Comparisons with results obtained from practical surface mount printed circuit board assembly of mobile telephones is discussed. From these, failure mechanisms are proposed to explain the failure of miniaturized multilayer ceramic capacitors under normal service conditions.

Polyaniline electrolytic capacitor

Abstract: Aluminum solid electrolytic capacitors with polyaniline doped with inorganic and organic acids as counterelectrode were fabricated, their properties were studied.

The effects of PECVD silicon dioxide passivation on the electrical characteristics of Sol-Gel deposited PZT film capacitors

Abstract: Plasma-enhanced chemical vapor deposition (PECVD) of doped and undoped silicon dioxide layers is widely used throughout the semiconductor industry for the passivation of processed devices before the final metallization processing steps. However, a reduction in the remanent polarization of PZT platinum-electrode capacitors has been observed when the capacitors were passivated with PECVD silicon dioxide films. This paper presents the results of a study to determine the effects of a standard PECVD silicon dioxide process on the retained polarization of Sol-Gel derived PZT capacitors with platinum electrodes. The retained polarization of the capacitors was measured before and after the silicon dioxide depositions. Measurements indicate that for PZT capacitors with temperature-stabilized top electrodes, there is relatively little change in the retained polarization after the depositions. However, for the PZT capacitors without the temperature-stabilized top electrodes, reductions in excess of 70% in t...

Decrease of inductance and electromagnetic interference in power electronics capacitors

Abstract: Pierron and Glaize (1992) have demonstrated that it is possible to decrease drastically parasitic inductances of wiring in commutation cells. But the inductance of capacitors still remains. Furthermore, in power electronics, problems of capacitors' inductance are well known: peaks of voltage in snubber capacitors (L dI/dt); output voltage ripples; perturbations in DC power supplies; low self-resonant frequencies (beyond this frequency, capacitors behave like an inductance), reduction of the lifetime of the whole circuit; switching capacitor disruption of operation of adjustable-speed drives; and especially electromagnetic interference (EMI). Here, from the study of standard capacitors, the authors have looked for solutions to reduce both inductance and EMI.

Imprint of ferroelectric PLZT thin-film capacitors with lanthanum strontium cobalt oxide electrodes

Abstract: The ferroelectric imprint is measured on thin-film PLZT capacitors with lanthanum strontium cobalt oxide top and bottom electrodes. The data show a significant amount of imprint with a combined elevated temperature and alternating (unipolar) voltage stress. No imprint was observed on samples that were temperature stressed without external bias.

Storage capacitors using high dielectric constant materials

Abstract: A storage capacitor having high dielectric constant materials and a method for forming same are described. The method solves the problems associated with fabrication of planar capacitors for DRAM chips constructed from inorganic oxides with perovskite structure. These materials are not readily etched by conventional ion etching techniques. These materials also react with silicon and silicon dioxide and the disclosed process avoids these interactions.