Showing papers on "Breakdown voltage published in 1970"

Avalanche injection and second breakdown in transistors

Abstract: A rapid type of second breakdown observed in silicon n+-p-n-n+transistors is shown to be due to avalanche injection at the collector n-n+junction. Localized thermal effects, which are usually associated With second breakdown, are shown to play a minor role in the initiation of the transition to the low voltage state. A useful tool in the analysis of avalanche injection is the n+-n-n+diode, which exhibits negative resistance at a critical voltage and current. A close correspondence between the behavior of the diode and the transistor (open base) is established both theoretically and experimentally. Qualitative agreement with the proposed model is obtained for both directions of base current flow. It is shown that transistors having thin, lightly doped collector regions are particularly susceptible to avalanche injection, which suggests that some compromise may be necessary in the design of high-frequency power transistors.

Electrical breakdown for uniform fields in compressed gases

Abstract: The electrical breakdown and prebreakdown characteristics of uniform fields in compressed gases are described. The failure of Paschen's law and the dependence of the breakdown voltage on the material, preparation and area of the electrodes, on the dust content of the gas, and on the type of applied voltage are included. The failure of the Townsend and streamer mechanisms of low-pressure breakdown is discussed, and a summary is made of the many suggested breakdown mechanisms for compressed gases. These are divided into three groups: breakdown due only to field emission of electrons, breakdown due to electron-field emission and space charge in the gas, and breakdown due to electron-field emission and charge collection on an electrode. The breakdown and prebreakdown characteristics are interpreted in terms of the various breakdown mechanisms, and the areas indicated where further investigations are needed. The surface flashover of insulating spacers in compressed gases is also briefly reviewed.

A New Instability in MOS Transistor Caused by Hot Electron and Hole Injection from Drain Avalanche Plasma into Gate Oxide

Abstract: Results of an experimental study are reported of a new instability found in p- and n-channel MOS transistors. This phenomenon is that when a higher voltage in an excess of a brakdown voltage is applied to the drain electrode the breakdown voltage drifts to a higher value and the drain current also increases. The origin of this instability is investigated by extensive measurements and analyses of the electrical characteristics of the transistors. It is concluded that 1) the semiconductor surface near the drain becomes p-like in the p-channel transistors and n-like in the n-channel transistors and thus the active channel length is shortened, 2) this is caused by charging of the gate oxide due to injection of electrons or holes generated during the drain avalanche breakdown, and 3) electron and hole injection is much affected by electric field across the oxide over the drain junction.

Transient responses of a pulsed MIS-capacitor

Abstract: Different transient responses occur at an MIS-capacitor, when a rectangular pulse voltage is applied. Depending on the d.c.-bias at the capacitor and the amplitude and polarity of the pulse voltage the transient response varies between 10 nsec and 1 sec. These transient responses are described theoretically and are compared to experimental data. A method for the direct measurement of the minority carrier lifetime is given. It is shown that the surface states dominate the recombination process, if the MIS-capacitor is pulsed from the inversion region into the accumulation region. This fact is used to determine the total number of surface states in the forbidden band and to explain the large a.c.-signal behaviour. In addition a simple and accurate method of measuring the breakdown voltage in the semiconductor is presented.

Dielectric Loss and Voltage Breakdown in Liquid Nitrogen and Hydrogen

Abstract: Cryogenic liquids have unusual physical properties. At low-voltage stress the dielectric loss in the cryogenic liquid is so small that it can not be accurately measured. As the voltage stress is increased, the dissipation factor increases to the order of 0.002, which is higher than for many conventional dielectric liquids. Both the voltage and the time of application influence the dielectric loss. Voltage breakdown is relatively high in both liquid hydrogen and liquid nitrogen. When pressure is increased somewhat at constant temperature to eliminate boiling, the electric strength is increased significantly. When the pressure is increased still further, the electric strength of the cryogenic liquid shows little or no additional increase. Cryogenic liquids have potential use as dielectrics in cable and other types of electrical apparatus. Studies of their dielectric prop-properties may improve the basic understanding of dielectric performance also.

Series lamp safeguard circuit

Abstract: A vehicle-headlamp-energizing circuit for headlamps connected in series. Each headlamp has a breakdown diode connected in parallel, and each breakdown diode has a breakdown voltage slightly larger than the normal potential drop across its parallel connected lamp so as to conduct current around the lamp when it fails and maintain conduction through the remaining lamps.

Complementary metal oxide semiconductor gate protection diode

Abstract: Gate protection is given to a complementary metal oxide semiconductor (CMOS) devices against excessive input voltage transients. An input diode which has a lower breakdown voltage than the gate oxide is attached to the input terminal to protect the gate oxide. The input protect diode is formed by diffusing an N+ region which overlaps both a P tube and an N substrate. The diffusion concentrations between the various regions determine the breakdown voltage of the protection diode. The overlapping relationship of the N+ diffusion over the P- tub and N substrate creates a structure which prevents parasitic NPN action.

New Phenomenon in Semiconductor Junctions—GaAs Duplex Diodes

Abstract: By the introduction of a deep center, a "polarizable" GaAs junction has been obtained which exhibits duplex or multiplex stable dc current-voltage characteristics. Each conduction state, "polarized" by a characteristic threshold voltage, appears to last indefinitely with low applied voltages at room temperature. This effect can be explained by assuming that the deep center, consisting of oxygen possibly in combination with other impurities, possesses an inherent bistability.

Graphical method for the determination of junction parameters and of multiplication parameters

Abstract: A graphical method is presented, which allows the determination, for a p - n junction, of the breakdown voltage and also the electric field distribution, the width of the depletion layer and the multiplication factor, all at a given reverse voltage. This method is based on the approximation of the exact impurity profile by an exponential function. The use of reduced parameters makes the method independent of the material. Numerical examples are presented.

Field-effect transistor with reduced drain-to-substrate capacitance

Abstract: A field-effect transistor having reduced drain-to-substrate capacitance is described as comprising a semiconductor substrate having a region of substantially lower resistivity than the substrate in the vicinity of the drain electrode. The region of low resistivity is of comparable depth to the drain region and produces devices having low drain-to-substrate capacitance and a higher drain-to-source ''''punch-through'''' voltage breakdown.

Transient voltage protection circuit

Abstract: A transient voltage protection circuit protects electronic devices coupled across a DC voltage source from transient voltages. A voltage breakdown device is employed to sense the voltage transients which appear across the voltage source. The voltage breakdown device is connected across the collector and the base junctions of a control transistor. A transient voltage above a predetermined magnitude will cause the voltage breakdown device to switch into impedance state thereby turning on the control transistor. The current flowing through the collectoremitter path of the control transistor is supplied as a control current to the bases of two parallel-connected shunting transistors which are driven into saturation when the control transistor is turned on. The shunting transistors are in a low impedance path across the source which includes a current limiting resistor and which loads the transient voltage in order to reduce its peak amplitude. When the shunting transistors are turned on, the voltage across the control transistor and the voltage breakdown device is reduced and the circuit elements are reset.

Individual device tuning using localized solid-state reactions

Abstract: THE CHARACTERISTIC PARAMETERS OF AN INDIVIDUAL SEMICONDUCTOR DEVICE IN AN ARRAY OR CIRCUIT ARE TUNED BY LOCALIZED HEAT TREATMENT CAUSING SOLID-STATE REACTIONS. NEIGHBORING DEVICES, IF ADEQUATELY SEPARATED, WOULD BE LITTLE AFFECTED. AS A RESULT, DEVICES IN AN ARRAY FOR EXAMPLE CAN EITHER BE VERY CLOSELY MATCHED OR ADJUSTED IN AN ARBITRARY OR STEP FUNCTION FASHION FROM DEVICE TO DEVICE. IN AN ARRAY OF DIODES FABRICATED FROM OXYGEN DOPED SILICON, FOR EXAMPLE, CURRENT IS PASSED (REVERSE OR FORWARD) THROUGH A SINGLE DIODE IN AN ARRAY. IF THE WHOLE ARRAY WERE AT 300*C. AND A SINGLE P+N DIODE WAS BIASED TO A LOCAL TEMPERATURE OF 500*C., THE DIODE WOULD BECOME MORE N-TYPE, THEREBY LOWERING IS BREAKDOWN VOLTAGE. CONVERSELY, AN N+P DIODE WOULD BECOME LESS P-TYPE, THEREBY RAISING ITS BREAKDOWN VOLTAGE.

Computer controlled device testing and subsequent arbitrary adjustment of device characteristics

Abstract: A system for arbitrary adjustment of device characteristics to produce parameter matched arrays or to do custom design utilizes computer control. The computer is linked with electron beam scanned testing to derive individual device characteristic information such as breakdown voltage, leakage, and switching time. From such derived information the computer generates a signal back to the electron beam, increasing its current intensity to heat the device and thereby change the device''s characteristic properties. If bulk breakdown voltage is too low, for example, increased current intensity shifts the material toward n-type if done at about 500* C. in an N p diode, this would increase bulk breakdown voltage. When it reaches the predetermined (computed) level, the beam cuts off.

Reset circuit for logic system in quiescent state for a predetermined time upon application of power and upon power fluctuations below a predetermined level

Abstract: A Zener diode is placed in series with the base of a transistor, which provides a reset signal when not conducting, to prevent conduction of the transistor until the breakdown voltage of the Zener is exceeded. An RC charging circuit is utilized to delay breakdown of the Zener diode for a specified time period after application of power to the system.

Particle initiated breakdown in compressed SF 6

Abstract: It is knownl1–3 that metallic particle contaminants can drastically reduce the breakdown voltage of compressed gases, but relatively little is known of the dependence of this effect on the test conditions, and of the breakdown mechanisms involved.

Planar p-n junction with mesh field electrode to avoid pinhole shorts

Abstract: A planar p-n junction semiconductor device, wherein an electrode surrounding a p-n junction is provided on a protective film covering the surface of a higher resistivity region of two regions of different conductivity types which form a p-n junction, another electrode is provided in a lower resistivity region in ohmic contact therewith, said two electrodes being electrically connected, and the space charge region is extended and the breakdown voltage of the p-n junction is enhanced when a reverse bias is applied to the p-n junction.

Thermal instability in very small p-n junctions

Abstract: Thermally induced second breakdown is studied in very small 6- to 10-volt silicon diodes having uniform breakdown. The formation of a small high-current density region is observed optically at the onset of thermal breakdown. Incremental resistance measurements can be used to determine nondestructively the threshold current for thermal breakdown. The threshold temperature for thermal breakdown is measured using the avalanche voltage temperature coefficient. The voltage drop associated with thermal breakdown is shown to be due to a sudden change in active area of the junction rather than to melting of the crystal.

Methods of controlling the reverse breakdown characteristics of semiconductors, and devices so formed

Abstract: The impurity density profile of p-n junctions in semiconductive devices is modified at localized regions of the junctions. This is achieved by a controlled oxidation process that causes a selective redistribution of impurities at such regions of the junctions. The process is particularly useful in the manufacture of reverse bias regulator diodes since it enables a controlled adjustment of the breakdown voltage with considerable precision. When the process is used in the manufacture of low voltage regulators, sharp reverse voltage breakdowns and other desirable electrical properties are obtained.

Power Amplification with Anomalous Avalanche Diodes

Abstract: The experiment described in this paper is performed for the purpose of obtaining additional information that might help to elucidate the operating principle of the anomalous mode. The diodes under investigation are of a silicon p/sup +/-n-n/sup +/ mesa structure. The breakdown voltage is 160 volts; the punch-through voltage is 60 volts. The test setup is similar to a conventional reflection-type amplifier with the diode mounted in a coaxial-cavity-like circuit. The reverse-bias pulse drives the diode to a low avalanche current level at which anomalous operation would normally commence. In this case, however, the tuning and loading of the cavity and its associated stubs is intentionally arranged to minimize free-running oscillations. Any residual RF power is reduced to the level of weak instabilities without any strong harmonics or subharmonic. Only in the presence of an input driving power with a frequency at or near the resonance frequency of the system, does an amplified power of the same frequency appear at the output port. Starting from the residual level the output power increases proportionally with the input power until at higher drives a saturation level is reached. In this particular case, operating at 410 MHz, saturation is reached at 18.5 watts with a maximum power gain of 12 dB and a bandwidth of 26 MHz. This output is approximately 20 to 30 dB higher in amplitude than any observable peak in the residual broad-band frequency spectrum Operating the diode as a free-running "hard" oscillator at the same current level and frequency, 18.8 Watts of RF power is obtained. The initial and steady-state power levels are substantially the same for both amplifier and oscillator. A plausible evaluation of these results can be obtained following van der Pol's differential equation for a forced negative-resistance oscillator.

Vacuum Breakdown Voltages of Dispersion-Strengthened Copper vs Oxygen-Free, High-Conductivity Copper

Abstract: Pairs of electrodes in vacuo at 10−9 Torr were tested at various gap spacings to find the amount of applied voltage needed to cause electrical breakdown, with a view to determining whether dispersion-strengthened (DS) copper has a higher breakdown voltage than standard, oxygen-free, high-conductivity (OFHC) copper. All anodes were made of OFHC copper. Half of these were paired with cathodes of OFHC copper, half with cathodes of DS copper. Voltage breakdown was determined for all pairs at gap spacings between 0.003 in. and 0.007 in. The group-average voltage breakdown of all DS/OFHC pairs was found to be 21% higher than that of OFHC/OFHC pairs. It is speculated that the relatively hard surface of DS copper may inhibit the growth of microprojections. In the softer-surface OFHC copper, microprojections might grow more easily and thus enhance the prebreakdown electrical field, leading to earlier breakdown.

High-Power TRAPATT Oscillations from Parallel-Connected Low-Cost Diodes (Correspondence)

Abstract: This paper reports successful parallel TRAPATT operation of a very low-cost commercial diode type. The best result achieved was a pulsed output of 225 watts at 700 MHz with an efficiency of 33 percent. The result was achieved by using three diodes in parallel. An explanation of the success of parallel operation is given. It is also shown that precise control of breakdown voltage is not necessarily required for parallel TRAPATT operation.

Corona and Breakdown Voltage in Helium-Oxygen Atmospheres

Abstract: Helium-oxygen mixtures are being considered for use in low-pressure (3.5 to 7.5 psia) compartments of manned spacecraft. Electrical wires, cabling, and components will be required to operate in these low-pressure compartments. During extra-vehicular maneuvers the pressure could decrease to that of space vacuum. During the depressurization and pressurization periods, corona and voltage breakdown will be a significant problem. This paper provides corona and voltage-breakdown data for electrical system components operating in these possible spacecraft environments. The breakdown voltage in pure helium, pure oxygen, and helium-oxygen mixtures is presented as measured between 5-cm-diameter parallel plates at various pressures and spacings at a frequency of 400 Hz and a temperature of 23°C. In addition, the corona onset voltages of twisted and spaced-parallel Teflon-insulated wires and wired connector contacts are presented.

Erratum: Low energy gamma-ray transitions in 237Np following α decay of 241Am

Abstract: Repetitive switching at 10 pulses/s with 1 ps pulses causes a rapid disintegration of the electrodes and a widening of the gap, so increasing the 'breakdown voltage. Immersion in liquid nitrogen increases the life, but again melting and thermal disintegration are observed. If this primitive device is encapsulated in epoxy resin, the lifetime greatly increases and operation at 10 pulses/s for a period of about 1 h is possible. In this case a gradual increase of the breakdown voltage is seen, as would be expected with a melting of the electrodes. It is assumed that encapsulation holds the structure together and inhibits thermal disintegration, thereby prolonging the life. The breakdown is associated with microheating beyond the melting point of gold (1000 "C), but this does not necessarily identify the process as thermal breakdown (O'Dwyer 1964). Any electronic breakdown mechanism which produces a conducting region of small enough volume results in rapid heating of this region. In our case, there is enough energy in the stray interelectrode capacitance to produce the observed damage. i he fast switching speed and low temperature switching favor an electronic breakdown. However, the initial breakdown region is so small that any interpretation is complicated by questions of homogeneity. The use of the more resistive, colloidal graphite electrodes inhibits filament formation and reduces the damage caused by rapid discharge of the stray capacitance. In this case the single pulse breakdown regions are not so clearly defined, but obvious melting effects can be seen after several pulses. Even if the breakdown is regarded as electronic in origin, the resultant heating causes melting, especially in ,maintaining the "on" state. We conclude that for this material, with these electrodes, the significant effect is thermal even for interelectrode spacings of 1 p. This simple technique can be used to study breakdown in a wide range of materials, particularly if the materials are not easy to prepare in thin film form.

Spark-discharge apparatus for electrohydraulic crushing

Abstract: In existing apparatus of the above kind, a capacitor is discharged through the liquid-immersed gap via a self-triggered or externally triggered switch device. In the present invention an initially uncharged capacitor is connected directly across the gap without any intervening switch device. This first capacitor is pulse-charged to the breakdown voltage of the gap via a step-up pulse transformer by discharging a second capacitor via a triggered switch device through the primary winding thereof. The two capacitors are approximately matched in value, as reflected by the transformer ratio, so that substantially all the energy stored in the second capacitor is transferred to the first capacitor at peak voltage thereon. A principal advantage is that the triggered switch device, eg a thyratron, does not require either to withstand the high gap voltage or to carry the high gap current.

Effect of Radio-Frequency Fields on the Electrical Breakdown of Vacuum-Insulated Electrodes

Abstract: Five possible mechanisms of dc vacuum breakdown are analyzed for rf electric fields. The theories which are considered are the vaporization of a micron‐sized cathode irregularity due to joule heating by field‐emitted electrons, vaporization of the anode due to bombardment by field‐emitted electrons, field‐emission current instability created by the presence of anode ions, exchange of electrode ions, and microparticle vaporization. The analysis indicates that mechanisms which do not involve anode ions in gaps of 0.2–1.0 cm will not be strongly influenced by rf fields in the frequency range of 20–120 MHz. Under similar conditions, the theories involving anode ions predict a very sizable increase in the voltage capability of vacuum‐insulated electrodes. Experimental ratios of vacuum breakdown voltage at 21.5 MHz to that for 60 Hz were experimentally determined for highly polished tungsten electrodes with separations between 0.18 and 0.61 cm. The rf voltages obtained experimentally were less than the values p...

DOUBLE INJECTION IN LONG p‐i‐n DIODES WITH DEEP DOUBLE‐ACCEPTOR IMPURITIES

Abstract: Double injection in long p‐i‐n diodes heavily doped with deep double‐acceptor impurities is discussed. Expressions for the current‐voltage relations in various regimes are derived, and an expression is given for the breakdown voltage characterizing the onset of the negative resistance. As an example, results for Zn‐doped Si are given using estimates of the capture coefficients.

Influence of triggering energy in lowering breakdown voltage of a trigatron spark-gap

Abstract: The reduction of breakdown voltage of a trigatron air-gap is related to the charge and energy of the triggering spark. Experiments were performed on a sphereplate trigatron spark-gap with the purpose of determining any direct dependence on lowering of breakdown voltage of either of the above characteristics. The experimental results have shown that the breakdown voltage reduces linearly as the triggering energy increases, irrespective of capacitor size or triggering voltage, and lead to the conclusion that the reduction of breakdown voltage depends directly on the energy of the triggering spark.

GATE-CONTROLLED SURFACE BREAKDOWN IN SILICON p-n JUNCTIONS

Abstract: In integrated circuits and MOS transistors made in silicon by the planar technique, the situation often arises that a metal electrode on top of the oxide layer passes over an underlying p-II junction. In that case the breakdown voltage (VBR) of the p-II junction can be modulated by the voltage (Vg) of the metal electrode. In this paper measurements on MOS transistors are given, which show that in the region where the surface is depleted, the breakdown voltage is given by VBR = Vg + constant. The constant is about proportional to the square root of the oxide thickness. A theoretical model is proposed which leads to good agreement with the measurements.

Breakdown Phenomena in Silicon p‐n Junctions Under Magnetic Field

Abstract: The effect of magnetic field on the reverse characteristics of silicon alloy junction diodes in the breakdown condition has been studied. The breakdown voltage caused by internal field emission has been found to remain unchanged under a magnetic field (maximum field used 15 kOe). On the other hand, the breakdown voltage occuring by avalanche ionization increased by about 15 mV on the application of a magnetic field. In the post‐breakdown region, while the magnetic field caused no change in current in diodes breaking down by the former mechanism, it increased the current (at constant voltage) in diodes having avalanche type of breakdown. Explanations of the observed results have been given.