Showing papers on "Breakdown voltage published in 1989"

Surface flashover of insulators

Abstract: The author reviews surface flashover (i.e. voltage breakdown along the surface of insulators), primarily in vacuum. He discusses theories and models relating to surface flashover and pertinent experimental results. Surface flashover of insulators in vacuum generally is initiated by the emission of electrons from the cathode triple junction (the region where the electrode, insulator, and vacuum meet). These electrons usually then multiply as they traverse the insulator surface, either as a surface secondary-electron-emission avalanche or as an electron cascade in a thin surface layer, causing desorption of gas which had been adsorbed on the insulator surface. This desorbed gas is then ionized, which leads to surface flashover of the insulator. The theory and modeling of this phenomena and experimental studies of surface charging, the applied voltage waveform, prestressing, conditioning, discharge delay and speed, insulator geometry AMD material, surface treatment, surface gases, temperature, and pressure are reviewed. Some suggestions are made regarding how to choose the material geometry and processing when selecting an insulator for a particular application. >

Pulsed Electrical Discharge in Vacuum

Abstract: 1. Introduction.- 2. Review of Vacuum Breakdown and Discharge Studies.- 2.1 The Electrode Surface in a Vacuum Discharge.- 2.1.1 Preparation of Electrodes.- 2.1.2 Determination of Micropoint Parameters.- 2.1.3 Effect of Emission from Non-metallic Inclusions.- 2.2 Vacuum Insulation, Properties and Breakdown.- 2.2.1 Prebreakdown Phenomena.- 2.2.2 Microdischarges.- 2.2.3 The Breakdown Voltage.- 2.3 Kinetics of Vacuum Electrical Breakdown.- 2.3.1 Characteristic Times of Breakdown.- 2.3.2 Role of Electrodes in the Development of Breakdown.- 2.3.3 X-Ray Pulse at Breakdown.- 2.4 Field Electron Emission to Vacuum Breakdown Transition.- 2.5 Hypotheses on Vacuum Breakdown Initiation.- 2.5.1 Physical Processes Leading to Vacuum Breakdown.- 2.5.2 Cathode-Initiated Breakdown.- 2.5.3 Anode-Initiated Breakdown.- 2.5.4 Comparison between Cathode and Anode Mechanisms for Breakdown Initiation.- 2.5.5 Microparticle-Initiated Breakdown.- 2.6 Spark Stage of Vacuum Breakdown.- 2.7 The Discharge Arc Stage. The Cathode Spot.- 2.7.1 Physical Properties of the Cathode Spot.- 2.7.2 Cathode-Spot Models.- 3. Experimental Equipment and Techniques.- 3.1 Electrical Measurement Techniques.- 3.1.1 High-Voltage, Nanosecond Pulse Generators.- 3.1.2 Current and Voltage Pulse Recording.- 3.2 Diagnostics of the Radiation that Accompanies Breakdown.- 3.2.1 Electro-optical Recording of the Light Emission.- 3.2.2 Photoelectrical Recording of the Light Emission.- 3.2.3 Spectral Investigation of the Discharge Plasma Radiation.- 3.2.4 X-Radiation Recording.- 3.3 Vacuum Equipment.- 3.4 Preparation and Examination of Electrode Surfaces.- 4. Pulsed Nanosecond Breakdown of Vacuum Gaps.- 4.1 Time Characteristics of the Pulsed Vacuum Breakdown.- 4.1.1 The Influence of Electrode Conditioning.- 4.1.2 The Influence of the Vacuum.- 4.2 Study of Light Emission at Pulsed Breakdown.- 4.2.1 Single-Shot Investigations.- 4.2.2 The Continuous-Operation Regime.- 4.2.3 Comparison with Other Data.- 4.3 Electrode Erosion Studies.- 4.3.1 Cathode Erosion.- 4.3.2 The Tracer Method.- 4.3.3 Anode Erosion.- 4.4 Nature of the Discharge Current at Breakdown.- 4.5 Mechanism of Pulsed Breakdown of Vacuum Gaps.- 4.5.1 The Role of the Cathode.- 4.5.2 The Cathode Plasma and the Electron Current.- 4.5.3 Anode Phenomena.- 5. Cathode Processes in a Pulsed Vacuum Discharge.- 5.1 EEE Initiation by High-Density FEE Current.- 5.1.1 Experimental Conditions.- 5.1.2 Description of EEE Current.- 5.1.3 The Point Explosion Delay Time.- 5.1.4 Calculation of the Emitter Heating.- 5.1.5 The Vacuum Discharge Delay Time.- 5.2 Erosion of Point Cathodes.- 5.2.1 The Fast Current Rise.- 5.2.2 The Slow Current Rise.- 5.2.3 The Point Erosion Rate.- 5.2.4 Erosion Due to Joule Heating.- 5.2.5 Comparison with Experiment.- 5.3 EEE Current Density Measurements.- 5.3.1 Current Density of a Point Cathode.- 5.3.2 Current Density from a Massive Cathode.- 5.3.3 Measurements Based on Erosion.- 5.3.4 Experimental Data.- 5.4 Microstructure of the Cathode Surface.- 5.4.1 Erosion Traces in SEM.- 5.4.2 The Field Enhancement Factor.- 5.5 The Contribution of Droplet Ejection to Cathode Erosion.- 5.6 Pressure in the Emission Zone.- 5.7 Formation of Cathode Microstructure.- 6. Cathode Flare Plasma.- 6.1 Velocity of CF Plasma Expansion.- 6.1.1 The Grounded Grid and Collector Method.- 6.1.2 The Photoelectric Method.- 6.1.3 The Transverse Magnetic Field Method.- 6.1.4 The Method of the Anode Erosion Mark.- 6.2 CF Plasma Parameters.- 6.2.1 CF Plasma Density.- 6.2.2 CF Plasma Composition and Temperature.- 6.3 EEE Current Effect on the Dynamics of the Plasma Light Emission.- 6.4 A Model for CF Plasma Expansion.- 6.4.1 The Adiabatic Model.- 6.4.2 MHD Calculation.- 6.4.3 The Model of an Ideal Plasma.- 7. Current Passage in the Spark Stage of Breakdown.- 7.1 Electron Emission from CF Plasma into Vacuum.- 7.2 Electron Emission from CF Plasma, Experimental Studies.- 7.3 Current-Voltage Characteristics of a Single-CF Diode.- 7.4 Dynamics of the CF Electron Emission Boundary.- 7.5 CF Plasma Potential Distribution and Plasma Emissive Properties.- 7.5.1 Probe Measurements of the CF Plasma Potential.- 7.5.2 The Nature of the Instability of CF Emission.- 7.6 Spark Current Between Broad-Area Electrodes.- 7.6.1 Calculation of the Spark Current Rise.- 7.6.2 The Role of Cathode and Anode Flares.- 8. Formation of New Emission Centers on the Cathode.- 8.1 Mechanisms of New EC Formation Under the Plasma.- 8.1.1 Mechanism of the Explosion of Micropoints.- 8.1.2 Mechanism of the Explosion of the Liquid Neck.- 8.1.3 Mechanism of the Breakdown of Non-metallic Inclusions.- 8.2 New EC Formation and Operation Under Cathode Plasma.- 8.2.1 Experiments Without Application of a Magnetic Field.- 8.2.2 Effect of Transverse Magnetic Field on New EC Formation.- 8.2.3 Results and Discussion.- 8.3 "Screening" Effect and Electron Beam Structure in a Diode.- 8.3.1 "Screening" Effect.- 8.3.2 Influence of Neighbouring CFs on the Electron Beam Structure in the Diode.- 9. Anode Processes in the Spark Stage of Vacuum Breakdown.- 9.1 Anode Heat Conditions.- 9.1.1 Power Density Deposited at the Anode.- 9.1.2 The Anode Temperature.- 9.2 Surface Structure of the Anode in the Discharge Zone.- 9.2.1 Summary of Previous Work.- 9.2.2 Metallographic Studies.- 9.2.3 Electron-Microscopic Studies.- 9.2.4 Mechanisms of the Anode Surface Damage.- 9.3 Formation of Anode Flares.- 9.3.1 Conditions for AF Formation, Its Composition and Temperature.- 9.3.2 The Expansion Velocity of AF.- 9.4 X-Radiation Generated at the Anode.- 9.4.1 X-Radiation on Discharging a Line.- 9.4.2 X-Radiation on Discharging a Capacitor.- 10. Fast Processes at DC Breakdown of Vacuum Gaps.- 10.1 Electrical Study of DC Breakdown.- 10.1.1 Electric Circuit.- 10.1.2 Prebreakdown Current and Breakdown Voltage.- 10.1.3 The Current Rise Time at Breakdown.- 10.1.4 X-Radiation and Electrode Erosion at Breakdown.- 10.2 Optical Studies.- 10.2.1 Determination of the Time of Appearance of Light.- 10.2.2 Electro-optical Breakdown Studies.- 10.3 Comparison with Results of Other Investigations.- 10.4 EEE Initiation at DC Breakdown.- 10.4.1 EEE Initiation under Pure Conditions.- 10.4.2 EEE Initiation and the Total Voltage Effect.- 10.4.3 Criteria for Vacuum Breakdown and EEE Initiation.- 11. Nonstationary Processes in the Vacuum Arc Cathode Spot.- 11.1 The Motion of Vacuum Arc Cathode Spots.- 11.1.1 The Effect of Surface Condition.- 11.1.2 The Influence of a Magnetic Field.- 11.1.3 Spontaneous Formation of Cathode Spots in Pulsed Arc Discharges.- 11.2 Response of the Vacuum Arc to Current Transients.- 11.2.1 Experimental Equipment and Technique.- 11.2.2 Results.- 11.3 Vacuum Arcs at Threshold Currents.- 11.3.1 The Threshold Current of a Vacuum Arc.- 11.3.2 Cathode Spot Current Density.- 11.4 Numerical Simulation of Processes in an Explosive Emission Center.- 11.5 Explosive Electron Emission and the Vacuum Arc Cathode Spot.- 12. Pulsed Electrical Discharge in Vacuum at Cryogenic Electrode Temperatures.- 12.1 Field Electron Emission at Low Cathode Temperatures.- 12.1.1 Effect of Superconductivity on FEE Current.- 12.1.2 The Nottingham Effect and Superconductivity.- 12.1.3 Other Emission Effects.- 12.2 Field Emission Current Preceding the Explosion of a Point.- 12.3 Characteristics of the Vacuum Discharge at Cryogenic Temperatures.- 12.3.1 Experimental Conditions.- 12.3.2 Experimental Results.- 12.4 Vacuum Discharge Between Electrodes Made of High-Temperature Superconductors.- 12.4.1 General Notions.- 12.4.2 FEE from High-Temperature Superconducting Cathodes.- 12.4.3 Vacuum Discharge.- References.

A model for switching impulse leader inception and breakdown of long air-gaps

Abstract: A mathematical model is described for continuous leader inception and breakdown of long gaps under positive switching impulses with critical time-to-crest. The model deals with rod, sphere, and conductor-plane gaps. It provides novel analytical expressions for continuous leader inception voltage, height of the final jump, and breakdown voltage as well as analytical tools to determine the critical electrode radius for any gap spacing. The theory is extensively compared with previous experimental results and is tested against several formerly developed empirical formulas, relevant to several discharge parameters, for different electrode forms and over a wide range of gap spacings. >

The influence of composition and Cr particle size of Cu/Cr contacts on chopping current, contact resistance, and breakdown voltage in vacuum interrupters

Abstract: A range of commercially produced Cu/Cr materials with different compositions (25% to 75% Cu) and Cr particle sizes (up to 160 mu m) has been investigated for their differences in chopping currents, contact resistance, breakdown voltage, contact erosion, and contact appearance. Test parameters have been chosen to reflect actual switching conditions. The properties of the Cu/Cr contact materials have been investigated after prestressing the electrodes with defined numbers of break arcs of 1 and 5 kA with alternating and unchanged polarity. It was found that the differences in properties of Cu75/Cr25 and Cu50/Cr50 contacts are minor as long as the same Cr particle size is used. Fine Cr particles increased the breakdown voltage and the rise in breakdown voltage after prestressing and the total erosion of contacts. While the mean chopping current values remained almost unaffected by fine Cr particles, the maximum values of chopping currents were deceased by using fine Cr particle sizes. Contact resistance and cathode surface structure after prestressing remained unaffected by a change in Cr particle size. >

Generation of intense pulsed electron beams by the pseudospark discharge

Abstract: A low-pressure gas discharge is presented as a source of intense pulsed electron beams. The pseudospark discharge emits a short-duration pinched electron beam during the breakdown phase. At voltages of typically 20 kV, approximately 10-20% of the total discharge current appears as the electron-beam current of typically 20 ns in duration. According to the breakdown voltage in the beam, a power density on the order of 10/sup 9/ W/cm/sup 2/ is reached. Thus, this electron beam turns out to be a good tool for material processing, comparable to pulsed high-power lasers. Besides the drilling of holes into metals and insulators, an interesting application is the production of high-temperature superconducting thing YBa/sub 2/Cu/sub 3/O/sub 7-x/ films. The electron beam is used to evaporate material from a stoichiometric 1-2-3 target. Experimental results concerning the propagation behavior in neutral gas, the electron energy distribution, and the interaction with matter are reported. >

Method of manufacturing a semiconductor device

Abstract: Oxygen ions or nitrogen ions are implanted into a semiconductor substrate to form a dielectric layer in the semiconductor substrate. An epitaxial semiconductor layer of at least 2 mu m in thickness, having excellent reproducibility and good crystallinity, is formed on a residual semiconductor layer on the dielectric layer by epitaxial growth, to serve as a region for forming semiconductor elements. Thus, a semiconductor device having high isolation breakdown voltage is impemented. Further, both oxygen ions and nitrogen ions are respectively implanted into a portions of a semiconductor substrate, which are adjacent to each other along the direction of thickness, to form two dielectric layers. Thus, a semiconductor device having higher isolation breakdown voltage is implemented.

A new concept for a non punch through IGBT with MOSFET like switching characteristics

Abstract: An IGBT (insulated-gate bipolar transistor) is presented which is based on bulk silicon material without a buffer layer. In contrast to other devices the carrier lifetime was kept as high as possible. It is shown that such a device with a breakdown voltage of 1400 V and a short-circuit capability of 1200 V at 20 V gate voltage has on-state and switching losses that are not higher-maybe even lower- than those of a buffer layer device if its backside p-emitter efficiency is kept low enough. >

Programmable memory matrix employing voltage-variable resistors

Abstract: A memory matrix comprises a plurality of word lines, a plurality of bit lines, and a stacked diode and voltage-variable resistor structure interconnecting bit lines to word lines. The stacked diode and voltage-variable resistor structure includes a doped region in a semiconductor substrate defining a work line, a doped polycrystalline silicon layer over said word line and forming a p-n junction therewith, and an amorphized region in the doped polycrystalline silicon layer having increased resistance over the non-amorphized portion of the doped polycrystalline silicon layer. A contact is made to the amorphized polycrystalline silicon material which preferably includes a titanium-tungsten barrier layer and an aluminum layer over the barrier layer. To improve the breakdown voltage of the diode structure, a region of opposite conductivity type is formed in the word line under the doped polycrystalline silicon layer either by out-diffusion of dopants from the polycrystalline silicon layer or by the implantation of dopant ions through the polycrystalline silicon layer into the word line.

Breakdown behavior of GaAs/AlGaAs HBTs

Abstract: Avalanche breakdown behavior at the collector junction of the GaAs/AlGaAs HBT (heterojunction bipolar transistor) has been studied. Junction breakdown characteristics displaying hard breakdown, soft breakdown, and negative resistance breakdown behavior were observed and are interpreted by analysis of localized microplasma effects, uniform microplasma-free behavior, and associated current gain measurements. Light emission from the collector-base junction of the GaAs/AlGaAs HBT was observed and used to investigate breakdown uniformity. Using a simple punchthrough breakdown model, the theoretical breakdown curves at different collector doping concentrations and thicknesses were computed and found to be in agreement with maximum breakdown voltages measured from devices displaying the most uniform junction breakdown. The serious current gain degradation of GaAs/AlGaAs HBTs at low current densities was analyzed in connection with the measurement of a large collector-emitter breakdown voltage. The unexpected functional relationship between the collector-emitter breakdown voltage and collector-base breakdown voltage is explained by the absence of a hole-feedback effect for devices not exhibiting transistor action. >

Statistical properties of electrical breakdown in vacuum

Abstract: The breakdown probability distribution function was determined for DC and impulse voltages, for conditions of gap pressure of 10, 0.1, and 10/sup -4/ Pa and gap length of 0.1 mm. It was found that DC and impulse voltages are associated with different types of probability distribution function due to different initiation mechanisms. The statistical influence of the number of previous breakdowns on the probability distribution of the breakdown voltage was investigated. By applying the U test for analysis of measured data, it was found that at lower gap pressure, the breakdown voltage probability changes after a smaller number of breakdowns than it does at higher gap pressure. >

Method and apparatus for non-contact opens/shorts testing of electrical circuits

Abstract: A circuit is tested for unwanted shorts and opens by positioning the circuit between a pair of electrodes in a chamber filled with an inert gas with the circuit conductors facing one of the electrodes. The circuit is charged by applying a selected voltage to the electrodes to produce an electric field extending generally perpendicular to the circuit, the voltage polarity being such that the one electrode carries the negative electrical charge. The circuit is then subjected to a pulsed laser beam brought to a focus between the one electrode and a selected spot on a conductor of the circuit so as to ionize the chamber gas at the beam focus to form a plasma so that an electric charge is imparted to that spot and to other circuit conductor portions having electrical continuity with that spot. The circuit is then discharged by reversing the polarity of the applied voltage and increasing the voltage magnitude substantially to the breakdown voltage of the chamber gas so as to form a glowing discharge plasma in the chamber gas opposite the charged portions of the circuit conductors. The circuit is observed to determine which portions of its conductors are glowing and therefore have electrical continuity with the selected conductor spot and which portions are not.

High efficiency single quantum well graded‐index separate‐confinement heterostructure lasers fabricated with MeV oxygen ion implantation

Abstract: Single quantum well AlGaAs/GaAs graded-index separate-confinement heterostructure lasers have been fabricated using MeV oxygen ion implantation plus optimized subsequent thermal annealing. A high differential quantum efficiency of 85% has been obtained in a 360-µm-long and 10-µm-wide stripe geometry device. The results have also demonstrated that excellent electrical isolation (breakdown voltage of over 30 V) and low threshold currents (22 mA) can be obtained with MeV oxygen ion isolation. It is suggested that oxygen ion implantation induced selective carrier compensation and compositional disordering in the quantum well region as well as radiation-induced lattice disordering in AlxGa1–xAs/GaAs may be mostly responsible for the buried layer modification in this fabrication process.

On the Dielectric Breakdown of Water: An Electrochemical Approach

Abstract: The dielectric breakdown of water under static fields has been studied by current‐potential relation for six metals. The relations are quasi‐linear up to a current density of a few A‐cm−2. The limiting current continues for a few volts to a few hundred volts, depending on the metal. A glow develops at the electrode and becomes continuous at the end of the plateau, where the current density increases irregularly (breakdown). The breakdown potential does not depend on the field in the water. It occurs at about the same current density for most of the metals. When electrolytes are added, the cell potential at the breakdown is decreased. Adsorbed layers and organic coatings increase the breakdown potential. Electrical energy storage in water is increased by ~10 times by coatings. The breakdown potential decreases with increase of log of rate constant for hydrogen evolution on the various electrodes and with the corresponding work function. The cell potentials for breakdown correspond to fields in the dielectric below that needed to dissociate it. The limiting current is caused by the formation of a layer at the interface, which causes increase in the electrode potential at constant current. The layer plasmolyzes. When the Fermi level in the cathode reaches the conduction band of water, electrons enter the water and remain stable therein. They interact nonadiabatically with water and are the head of streamers. An analogous model holds for holes in the valence band. "Dielectric breakdown" depends on the Fermi level of the electrons in the condenser plate and the semiconductor characteristics of water. It can be eliminated by modifying the electrode surface.

Half-micron CMOS on ultra-thin silicon on insulator

Abstract: A 0.5- mu m CMOS technology on ultrathin SIMOX SOI (silicon-on-insulator) material with silicon film thickness of 80 nm is studied. When compared with bulk devices the SOI NMOS devices showed a slightly reduced current-drive-capability, a small negative differential output conductance at high gate bias, and a strongly reduced breakdown voltage. Floating-substrate effects remain significant even for SOI devices on ultrathin material. The hot-carrier degradation of the SOI NMOS devices was significantly enhanced by electron injection in the buried oxide layer. The performance of ring oscillators on SOI material was excellent. Furthermore, fully functional 2K SRAM circuits were fabricated. The main advantages of ultrathin-film SOI seem to be the improved circuit properties and the simplified fabrication technology. The reduction of the floating-body effects in the devices on ultrathin-film SOI is required to make SOI a competitor to bulk material for future deep submicron CMOS. >

Interface properties of HgCdTe metal‐insulator‐semiconductor capacitors

Abstract: The conductance method has been used to measure the density of interface states of the ZnS/Hg0.775Cd0.225Te metal‐insulator‐semiconductor (MIS) system with three different HgCdTe surface treatments. It is found that the density of fast interface states increases from ∼1011 eV−1 cm−2 at the conduction‐band minimum to ∼1013 eV−1 cm−2 near the valence‐band maximum. In addition, the interface states located in the lower part of the band gap communicate with the valence band so efficiently that the effective band gap is reduced. Our observations explain why the p‐type MIS photodiode is superior to the n‐type version in terms of breakdown voltage and storage time.

Method for determining the breakdown voltage in gas-filled tubes

Abstract: Average values of the dynamic breakdown voltage [Ubar]p as a function of the rate of increase of the applied voltage k for a nitrogen-filled tube with bulk copper electrodes one of which is gold plated are presented in this paper Extrapolating the resulting curve up to the intercept with the Up-axis allows the value of the static breakdown voltage to be found It is shown that the value of static breakdown voltage depends on the cathode material regardless of whether the tube has been irradiated with 60Co The distribution densities of 250 values of the dynamic breakdown voltage for values of the rate of increase of the applied voltage of 01 Vs−1 and 1Vs−1 are given It is shown that the agreement between the experimental values and the theory are better for a rate of 01 Vs−1

Integrated power DMOS circuit with protection diode

Abstract: Methods and circuits of integrated DMOS, CMOS, NPN, and PNP devices include self-aligned DMOS (411) with increased breakdown voltage and ruggedness for recovery from transients including additional Zener diodes (402/474).

High-performance salicide shallow-junction CMOS devices for submicrometer VLSI application in twin-tub VI

Abstract: A 3.3-V CMOS technology with 0.6- mu m design rules in sixth-generation twin-tub CMOS (twin-tub VI) was developed. The major features of the device in this technology are: HIPOX twin-tub structure, n/sup +//p/sup +/ dual-type poly gate, 125-AA thin gate oxide, shallow junctions, rapid thermal anneal activation, and thin TiSi/sub 2/ as the source/drain/gate silicide layer. Electrical measurements show good I-V characteristics, ideal low junction leakage, latchup immunity for 4.5- mu m n/sup +/-to-p/sup +/ spacing, more than 6.0-V NMOSFET snapback breakdown voltage, good hot-carrier aging properties, and undetectable dopant interlateral diffusion through a TiSi/sub 2/ shunt layer of a different type of poly. The transistors were scaled to 0.45- and 0.40- mu m effective channel length without punchthrough at V/sub ds/=3.6 V for NMOS and PMOS, respectively. A 100-ps stage delay was obtained on a 101-stage CMOS ring oscillator at an operating voltage of 3.3 V. >

Methods of increasing the surface flashover potential in vacuum

Abstract: The effects of surface coating and magnetic fields on dielectric surface breakdown in vacuum are described. Coatings of metals and meta oxides increase the pulsed surface hold-off voltage by factors of up to three, depending on the material. Measurements of the secondary emission coefficient show substantial differences between coated and uncoated samples at high energies. The influence of magnetic fields on dielectric surface breakdown for uncoated samples is investigated in the pressure range of 10/sup -5/ to 1 Pa, for both DC and pulsed electric and magnetic fields. Insulation effects (increase in breakdown voltage of up to 2* at magnetic field amplitudes of 0.5 T) are observed when the magnetic field is parallel to the surface of the dielectric and perpendicular to the applied electric field. Magnetic insulation shows a strong material dependence and decreases with increasing pressure and surface roughness. >

Monolithic microwave integrated circuit terminal protection device

Abstract: A monolithic microwave integrated circuit is enclosed within an ionizable gas filled housing having a terminal protection device integral with the circuit's substrate. A photon generating region extends within the substrate and along a portion of the surface area of the substrate for facilitating the ionizing of the gas. First and second electrodes, in contact with the substrate surface area and disposed on opposite sides of the photon generating region, have a plurality of cantilevered protrusions extending over the surface of the substrate and equally spaced from one another forming spark-gaps therebetween. One electrode is connected to an input to the device while the other is connected to ground. When a potential difference between the first and second electrodes increases towards a predetermined value, due to high RF input energy, the photon generating region is operatively biased to emit photons, which ionize the gas, resulting in a voltage discharge across the spark-gaps to occur quickly and at a lower voltage than the semiconductor breakdown voltage.

Semiconductor device and method of producing the same

Abstract: Source and drain electrode metals of a field effect transistor having a recessed gate electrode metal are directly connected to a high impurity concentration semiconductor layer which faces the gate electrode metal through an insulator film which defines the side wall of the recess The source and drain electrode metals may be disposed so as to face the gate electrode metal through the side insulator film With this arrangement, it is possible to lower the parasitic resistance between the gate electrode and another electrode of the field effect transistor, to lower the contact resistance between a semiconductor layer and the source and drain electrodes, to reduce the capacitance of the recess gate electrode and to increase the source-gate breakdown voltage, advantageously The above-described arrangement is particularly suitable for a transistor employing a compound semiconductor, and can also be applied to semiconductor devices other than field effect transistors Such semiconductor devices can readily be produced by forming a gate electrode metal with a self-alignment process using the lift-off method

Electric breakdown under quasi-uniform field conditions and effect of emission shields in polyethylene

Abstract: Electric breakdown strengths were measured using a quasi-uniform field spherical electrode assembly for polyethylene with and without an emission shield between the electrode and the polyethylene surface. The results show that the emission shield suppresses carrier injection from the electrodes and enhances the breakdown strength. The short-circuit breakdown strength is always lower than the normal breakdown strength under DC voltage conditions. With the carrier injection from one electrode suppressed by an emission shield, polarity effects during breakdown were observed. These effects, for measurements using a quasi-uniform field electrode assembly, are similar to those measured using an extremely nonuniform field needle-plate electrode assembly. The AC breakdown strength measured under quasi-uniform field conditions is about the same as that measured under extremely nonuniform field conditions, and it is also not much affected by the DC bias voltage. All of the breakdown phenomena can be interpreted on the basis of K.C. Kao's et al. (1982) electrical discharge and breakdown model. One significant finding is that a suitable emission shield and a suitable method of reducing the energy released from nonradiative transition due to trapping and recombination may greatly improve the breakdown behaviour for high voltage polymeric-insulated cables. >

Investigations of pulsed surface flashovers for the triggering of pseudospark high-power switches

Abstract: Surface discharges over insulators in vacuum under rectangular high-voltage pulses are investigated. These discharges are among the methods used to trigger pseudospark switches. Low breakdown voltage and long lifetime are the requirements these insulators have to meet to be used as trigger materials. For this purpose the breakdown behavior of certain ceramics stressed by high-voltage pulses was investigated in an oil-free vacuum of 10/sup -5/ Pa. The erosion of the insulator by the discharge plasma was investigated with a scanning electron microscope. An evaluation of the measurement and a comparison of the properties of the investigated insulators show that SiN, Al/sub 2/O/sub 3/, and CaTiO/sub 3/ have low breakdown voltages and exhibit the lowest erosion rates. First results obtained with these materials as trigger insulators in pseudospark switches are promising with regard to the achieved lifetimes. A lifetime of four million triggered discharges under 90% switch current reversal was reached at a peak switch current of 25 kA without a serious reduction in trigger performance. >

On the electrical breakdown of gaseous dielectrics-an engineering approach

Abstract: Quantitative criteria are derived for the onset of breakdown in atmospheric air and similar weakly electronegative gases. A comparable criterion is then formulated for strongly electronegative gases such as SF/sub 6/. These criteria contain no quantities other than those which can be obtained directly from breakdown voltage measurements in a uniform field, i.e. from Paschen curve data. No specific data are required for the ionizing coefficients of the gas. The advantage, from an engineering point of view, is that it is much easier to perform reliable Paschen curve measurements than it is to measure ionization growth parameters. The price paid is that criteria formulated in this way cannot be used to yield unknown Paschen curves. The criteria can be applied to any nonuniform field configuration provided the electrostatic field distribution is known. Moreover, in many cases a simple analytical approximation to the field distribution can render an extensive calculation of the electrostatic field unnecessary. The discussion deals exclusively with situations in which the onset of breakdown in the system is synonymous with the onset of a corona discharge. >

Hidden zener diode structure in configurable integrated circuit

Abstract: In one embodiment of the invention, a P diffused region, acting as an anode of a zener diode, is formed within an N+ sinker which is part of a vertical transistor in a configurable integrated circuit. This N+ sinker contacts an N+ buried layer or an N+ substrate and provides an exposed contact region for the transistor. Conductivity types may, of course, be opposite to those described in this embodiment. In this way, an additional zener diode is made available to a user without requiring additional die area. Additionally, since the zener diode is not formed from emitter and base regions of a bipolar transistor, the breakdown voltage of the zener diode may be set as desired. By forming a P zener diode anode in all N+ sinkers, or, conversely, forming a N zener cathode in all P+ sinkers, a large number of zener diodes may be made available to a user without adding any die area to the configurable integrated circuit.

Electrical breakdown of SF/sub 6/ at small values of the product pd

Abstract: The breakdown of SF/sub 6/ when static and impulse voltages are applied at small values (from 10/sup -4/ bar-mm to 1 bar-mm) of the product pd was investigated. It was found that the prevailing breakdown mechanism up to 8*10/sup -3/ bar-mm was the Townsend mechanism. Between 8*10/sup -3/ and 5.5 bar-mm the Townsend and streamers mechanisms combined, whereas from 5.5 bar-mm on the streamers mechanism took over. The Paschen law was found to hold for the points lying to the right of the minimum when static voltage was applied, whereas edge-type breakdown occurred on the points lying to the left of the minimum. When impulse voltage was applied, the Paschen law was valid only for the points to the right of the 1 bar-mm point. The electrode material affected the static and impulse breakdowns through the values of its work function. >

High-speed Ga/sub 0.47/In/sub 0.53/As MISIM photodetectors with dielectric-assisted Schottky barriers

Abstract: A technique is described for fabricating high-speed metal-insulator-semiconductor-insulator-metal (MISIM) photodetectors for high-speed fiber-optic systems. These devices make use of a Langmuir-Blodgett film enhanced Schottky barrier to achieve broadband linear response to 13 GHz at low bias voltage (5 V) with approximately 0.9 A/W external responsivity, 15 V breakdown voltage, and approximately 2 mu A dark current. A gain of about 2 and a 5% tail in the temporal response are analyzed. The needed bias and the device processing are compatible with those for integrated receivers. >