Showing papers on "Breakdown voltage published in 1976"

Zener and avalanche breakdown in As-implanted low-voltage Si n-p junctions

Abstract: Implanted-diffused As layers in Si have been well-characterized and have been used in fabricating low-voltage n-p junctions. It is shown that these As layers form linearly graded junctions with a uniform B-doped background (ρ ≃ 0.006 Ω.cm). The grade constant of the As profile at the junction is known sufficiently well as a function of As dose, diffusion time, and temperature to allow quantitative use of existing tunneling and avalanche theories for the calculation of the reverse I-V curves. Following a verification of the calculated I-V curves and their temperature dependence as a function of grade constant, calculated curves are presented which correlate As implant dose and diffusion with junction breakdown voltage, breakdown impedance, and temperature coefficient of reverse voltage. The temperature coefficient is shown to change from negative to positive as the transition from tunneling to avalanche occurs. In addition, the relative importance of tunneling and multiplied-generation current as a function of current density is elucidated for any particular As layer grade constant.

Analytical solutions for the breakdown voltage of abrupt cylindrical and spherical junctions

Abstract: Analytical solutions for the breakdown voltage of abrupt cylindrical and spherical junctions have been obtained, using suitable approximations for the electric field in the depletion layer. These solutions are shown to be within ±1% of exact computer solutions for doping densities of less thant 10 16 cm −1 . By normalization to the parallel plane case, these solutions have been presented in a form which allows the computation of the breakdown voltage of both cylindrical and spherical junctions using a single curve for each situation.

Partial discharge characteristics of oil-immersed insulation systems under DC, combined AC-DC and DC reversed polarity voltage

Abstract: Breakdown characteristics of insulating oil, under combined ac-dc voltage and dc reversed polarity voltage, and partial discharge characteristics of oil-immersed insulation, under combined ac-dc voltage and polarity revesal of dc voltage Were made clear by elementary experiments. After that, a numerical dc field mapping method for electric field analysis of two-dimensional configurations which consist of composite insulation and field mapping methods under combined ac-dc voltage and dc reversed polarity voltage were proposed. Futhermore, partial discharge characteristics of transformer insulation under dc, combined ac-dc voltage were experimentally made clear by practical trial models.

A computer-aided design model for high-voltage double diffused MOS (DMOS) transistors

Abstract: High-voltage double diffused metal-oxide semiconductor transistors (DMOST's) have been fabricated with drain-source breakdown voltage greater than 200 V. This paper describes an experimental and theoretical study of the current-voltage behavior of these devices leading to a two-component MOS field effect transistor (MOSFET)-resistor model appropriate for computer-aided circuit design. The effects of velocity saturation, mobility reduction, and nonuniform impurity concentration in the channel, and of spreading resistance in the drift region are considered. Parameter extraction for experimentally characterizing these effects is described. Comparison of experimental and theoretical results shows that the model accurately predicts the device I/V characteristics. The range of validity of the model is limited primarily by high current saturation effects.

Onset or breakdown voltage reduction by electrode surface roughness in air and SF 6

Abstract: This paper describes investigations on the influence of surface roughness on the onset or breakdown voltage in air and SF 6 . Applying the streamer theorie of electrical discharges the role of ionization characteristic, gas pressure, shape and size of electrode surface protrusions is discussed. The maximum allowable field gradients of electrode surfaces with hemispherical, spherical, and filamentary irregularities were computed in air and SF 6 . Pictures of a sparked electrode surface, showing slze and shape of surface roughness, were made using an electron scanning microscope. A comparison between computed breakdown field gradients of rough electrodes and experimental results obtained by employing different electrode configurations in a wide pressure range confirmed the theoretical considerations.

Importance of the dependence of the secondary electron emission coefficient on E/p0 for Paschen breakdown curves in ac plasma panels

Abstract: Apparent deviations from Paschen’s law, observed in ac plasma panels, have been resolved by generalizing the breakdown criterion to include the dependence of the secondary electron emission coefficient on E/p0. Incorporation of this dependence into the proposed effective coefficient involves consideration of both the back‐diffusion phenomenon and the influence of E/p0 on the efficiency of metastable atom generation. Calculated voltage breakdown curves in pure neon and neon plus 0.1% argon mixture are in good agreement with experimental data for both the metal electrode dc discharges and the insulator‐covered electrode discharges found in ac plasma panels.

Avalanche breakdown in high-voltage D-MOS devices

Abstract: A new type of voltage breakdown occurring in high-voltage D-MOS transistors is described. This effect severely reduces the high-voltage capability of these devices when the gate field plate is extended through the drift region toward overlapping the n+drain contact region. The breakdown is shown to be due to an avalanche phenomenon appearing close to the n+region, due to the very high field induced in this NIOS structure in nonequilibrium. A first-order theory is developed to confirm the conclusions of the experimental study.

Investigation of the transition from tunneling to impact ionization multiplication in silicon p-n junctions☆

Abstract: White noise spectra of diodes breaking down between 1·5 and 5 V have been used to investigate the details of the transition from tunneling to avalanche breakdown in silicon p-n junctions. It is found that the transition and carrier multiplication in these junctions is dominated by the influence of the threshold energies for ionization. Because this influence is not explicitly taken into account in the existing theories of carrier multiplication and noise, they are not applicable to low breakdown voltage diodes. Consequently, a multiplication onset model and alternate schemes for calculating the DC multiplication and noise in low breakdown voltage diodes are developed. Analysis of the noise data indicates that the threshold energies for ionization depend slightly on junction widths and, for the diodes employed in this study, range between 1·66–1·9 eV for electrons and 1·79–2·04 eV for holes. The minimum distance between ionizing collisions is found to range from 190 to 240 A for electrons and 200 to 250 A for holes. Application of the threshold energies for ionization to the multiplication onset model permits evaluation of the doping densities on both sides of the step junctions. From it, it is determined that the solubility of aluminum in silicon is NA = 9·5 ± 0·5 × 1018 cm−3.

Power GaAs MESFET with a High Drain-Source Breakdown Voltage

Abstract: A power GaAs MESFET with a high drain-source breakdown voltage in excess of 17 V has been developed. A selective GaAs epitaxial process is introduced to form "inlaid" n+ source and drain regions that can provide a high drain-source breakdown voltage and a low ohmic-contact resistance. Typical characteristics of the MESFET composed of two-cell units are as follows:

Semi-Insulating Polycrystalline-Silicon (SIPOS) Films Applied to MOS Integrated Circuits

Abstract: A semi-insulating polycrystalline-silicon (SIPOS) film doped with oxygen atoms is deposited on the surface of silicon substrates by a chemical vapor reaction of silane and nitrous oxide in nitrogen ambient, and has been studied for the surface passivation of MOS-IC's, in particular, C/MOS-IC's of channel-stopperless structure. SIPOS films are semi-insulating and intrinsically neutral. A double-layer system consisting of 3000 A SIPOS and 6000 A SiO2 films is employed as a replacement of a thick silicon dioxide layer in C/MOS-IC's of channel-stopperless structure and exhibits excellent field-passivating properties, namely, a small drain-source leakage current, a high drain breakdown voltage, and a high parasitic threshold voltage. Furthermore, the silicon surface passivated by SIPOS films shows high stability under a severe bias-temperature stress. It is concluded that C/MOS-IC's passivated by SIPOS films are not required to have a channelstopper diffusion region and can be operated at high applied voltages, which leads to higher integrating density and higher reliability.

Chemical Vapor Deposition of Tantalum Pentoxide Films for Metal‐Insulator‐Semiconductor Devices

Abstract: Thin amorphous Ta/sub 2/O/sub 5/ films were deposited by oxygen-assisted pyrolysis of tantalum dichloro-diethoxy-acetylacetonate. Index of refraction and the optical gap measurements of the films were in agreement with previous results. The d-c conduction mechanism appears to be bulk limited following the Poole-Frenkel mechanism with transition towards a space charge limited current at high current densities. The conduction level is high and breakdown voltage is low with respect to SiO/sub 2/ or Si/sub 3/N/sub 4/. The higher dielectric constant of Ta/sub 2/O/sub 5/ films could make them attractive in double layer insulator MIS devices.

Silicon-on-sapphire mesa transistor having doped edges

Abstract: Instabilities in the leakage current and threshold voltage of a field effect transistor on an insulator substrate, at both room temperature and after operation at relatively high temperatures (150° C), are substantially reduced by selectively doping edge regions adjacent the transverse side surfaces of the channel region of the field effect transistor, wherein the breakdown voltage of the channel-to-drain junction is substantially increased Atoms are placed in these edge regions to provide therein a carrier concentration of at least 5 × 10 16 atoms-cm -3 of the opposite conductivity type to that of the source and drain regions The doped edge region extends partly across said channel region and extends fully across the side surface at the end of the source region

Silicon avalanche photodiodes with low multiplication noise and high-speed response

Abstract: Low-noise and high-speed silicon avalanche photodiodes with low breakdown voltage are reported. The diode structure with a low-high-low impurity density profile is proposed to have low-noise characteristics. Multiplication noise and depletion layer width of several structures are compared theoretically, and effects of impurity density profile of the avalanche region are discussed. Built-in field is also provided to realize high-speed response without increasing operating voltage. Silicon avalanche photodiodes with the above mentioned structure have been fabricated with long time substrate annealing, ion implantation, and epitaxial growth. Attained performances are as follows: noise parameter k = 0.027 - 0.040, output pulse half width τ = 260 ps for a mode-locked Nd:YAG laser pulse, gain-bandwidth product up to 300 GHz at M = 400, quantum efficiency 0.55 - 0.66 at the 0.81- to 0.83-µm wavelength, and breakdown voltage about 100 V.

Influence of rain on switching impulse sparkover voltage of large-electrode air gaps

Abstract: The paper deals with a laboratory investigation into the influence of rain on the switching impulse sparkover characteristics of large-sphere and toroid plane air gaps. Tests were also carried out on coneterminated rod-plane gaps for reference purposes. The factors investigated include the high voltage electrode geometry, nature of the surface, rain intensity as well as the impulse form and polarity. Attention is also paid to the influence of rain on the statistical dispersion of the sparkover voltage and on the nature of the cumulative probability curve. A general correlation, valid for a wide variety of electrodes, has been established between the mean spark-over voltage gradient for positive switching impulses under dry conditions, and the corresponding influence of rain on the breakdown voltage.

Method of making ion implanted zener diode

Abstract: A method of making a zener diode having an accurately predetermined breakdown voltage. A discrete device and integrated circuit adaptation of this device is disclosed. A specially highly doped opposite conductivity type island is embedded in a high resistivity body portion. Embedded in the body portion contiguous the island is an ion implanted surface portion of the one conductivity type. The surface portion has an accurately predetermined concentration of conductivity determining impurity atoms in the range of about 1 × 10 16 to 1 × 10 19 atoms per cubic centimeter. A PN junction having a high breakdown voltage separates the island from the body. A PN junction having a lower but accurately predetermined breakdown voltage separates the island from the surface portion and forms a zener junction. In integrated circuit adaptations, this device preferably shares a transistor electrode for a transistor junction that is to be protected from overvoltage effects.

Method of making a junction type field effect transistor

Abstract: In the manufacture of a vertical structure junction type field effect transistor, the formation of a gate region is followed by an oxidation treatment of the upper surface of the gate region and then by the growth of a semiconductor layer consisting of a monocrystalline region on the channel portion and a polycrystalline region on the oxide film formed on the gate region The existence of the oxide film on the gate region prevents the out-diffusion of the impurity doped in the gate region, preventing the lowering of the breakdown voltage, and enabling a short channel length and small series resistance of the channel

High-gain, high-voltage transistor for linear integrated circuits

Abstract: A semiconductor structure for, and method of manufacture of, a linear integrated circuit provides the equivalent of a base function in a transistor, wherein the base function has a dual charge density, with the latter being relatively low in the lower active area of the base between PN junctions for high gain and high breakdown voltage, but high along the upper surface to prevent an unwanted inversion layer from occurring.

Protection circuit for insulated-gate field-effect transistors (IGFETS)

Abstract: The gate of an IGFET, which is directly connected to the input terminal of a circuit is protected by means of first and second diodes connected between the gate and first and second points of operating potential, respectively. The first diode is poled to conduct current in the forward direction when the potential at the gate is more positive than the potential at the first point and the second diode is poled to conduct current in the forward direction when the potential at the gate is more negative than the potential at the second point. A high conductivity diode means is connected between the first and second points of potential. The reverse breakdown voltage (VR) of the first and second diodes is greater than the VR of the diode means whereby the first and second diodes conduct only in the forward direction while the diode means conducts in the forward or reverse direction.

Double Injection in Semiconductors

Abstract: A new model for double injection in high‐resistivity semiconductors, containing recombination centers, is proposed. The negative resistance is associated with the presence of a saturated trap region near the minority‐carrier injecting contact, which extends toward the opposite contact for increasing current. By using the regional approximation method, an analytical current‐voltage characteristic is obtained which describes both the prebreakdown and negative‐resistance regime. The present theory shows that the deviation from the quadratic J‐vs‐V behavior in the prebreakdown regime depends upon the interelectrode separation and gives a good fit for the prebreakdown characteristic of Au‐GaP diodes. The theoretical breakdown voltage decreases with increasing thermal free‐carrier concentration, and good quantitative agreement is found for the experimental results for GaP and InSb double‐injection diodes.

Effect of electrode surface roughness on breakdown in nitrogen/SF6 mixtures

Abstract: Breakdown voltages in uniform-field and coaxial-electrode systems have been calculated for nitrogen/SF6 mixtures at pressures up to 5 bar for smooth electrodes, and for electrodes whose surface roughness is represented by a hemispherical protrusion. The calculations show that the addition of nitrogen to SF6 reduces sensitivity to electrode surface condition. For practical systems, having values of the product (pressure × roughness) of 50-500 bar μm, this tends to offset the loss of dielectric strength predicted for smooth electrodes with the addition of nitrogen. With a 30μm protrusion, for example, the breakdown voltage at 4 bar of a 70 mm/220 mm coaxial system containing 70% nitrogen by volume exceeds that for pure SF6. The results of the calculations are compared with uniform-field measurements with an artificial cathode protrusion and with published data for a.c. and impulse breakdown in a coaxial-electrode system.

The theory and application of a simple etch contour for near ideal breakdown voltage in plane and planar p-n junctions

Abstract: It is shown that high avalanche breakdown voltage in both plane and planar p-n junctions can be achieved by extending the heavily doped side of the junction beyond the contact and partially etching into it. This forces the depletion region to spread back some distance in the heavily doped side. The technique, when properly applied, is capable of giving virtually ideal breakdown voltages for both plane and planar type p-n junctions and uses only a fraction of the area required for a typical negative bevel. The actual breakdown voltage depends on how carefully the etch is controlled. For planar junctions, the breakdown voltages that can now be achieved are better than any previously reported. Moreover, since the technique is based on etching, mechanical contouring is avoided. This, in itself, is beneficial. Both the new method, termed the depletion etch method (DEM), and the negative bevel technique are discussed using a simple theory of charge balancing which appears to simplify qualitative comparison of different geometries used to increase avalanche breakdown voltage. From this theory, it is easy to see why the new method is potentially superior in terms of peak surface to peak bulk field trade-off. Exact numerical three-dimensional (with radial symmetry) electric field calculations as well as a number of experimental results using both plane and planar junctions bear out the predictions of the simple theory. Moreover, both the calculations and the experiments performed to date show that close to the ideal p-n junction, breakdown voltage can be reached for both plane and planar type p-n junctions if the etch depth can be controlled with sufficient precision.

Influence of the secondary electron emission coefficient of argon on Paschen breakdown curves in ac plasma panels for neon+0.1% argon mixture

Abstract: A generalized expression has been derived for the effective secondary electron emission coefficient γ, in Penning mixtures which incorporates the effect of both the majority and minority ions. Specific calculations for ac panels having an Ne+0.1%Ar mixture show that even a relatively small value of γAr not only significantly lowers the breakdown voltages, but also moves the voltage minimum to higher p0d values and makes the right‐hand side of the Paschen curve less steep. This sensitivity of the effective coefficient γ on γAr is sufficient to explain the critical dependence of the shape of the measured breakdown voltage curves in ac panels on minor changes in the surface properties of the deposited insulator surfaces.

A general method for predicting the avalanche breakdown voltage of negative bevelled devices

Abstract: In this paper, the concept of an effective negative bevel angle is introduced. It is shown that the fraction of the ideal breakdown voltage that is attained for virtually any negatively bevelled diffused junction device is a single function of this effective bevel angle. These results can be used to calculate the breakdown voltage for diffused junction devices over the range of commonly used negative bevels. The effective bevel angle is shown to be the product of the actual bevel angle and the square of the ratio of the depletion width on the lightly and heavily doped sides of the junction for the ideal device at breakdown. Consideration is also given to abrupt junction devices. In the final section, an approximate means for correcting these results for variations in the passivant dielectric constant and the introduction of surface charge is presented.

Testing of typical spacecraft materials in a simulated substorm environment

Abstract: An investigation to determine spacecraft materials characteristics under charging conditions was conducted at the Lewis Research Center substorm simulation facility. The test specimens were spacecraft paints, silvered Teflon, thermal blankets and solar array segments. The samples, ranging in size from 300 to 1,000 sq cm were exposed to monoenergetic electron energies from 2 to 20 keV at a current density of 1 nA sq cm. The samples generally behaved as capacitors with strong voltage gradients at their edges. The charging characteristics of the silvered Teflon, Kapton, and solar cell covers were controlled by the secondary emission characteristics. Insulators that did not discharge were the spacecraft paints and the quartz fiber cloth thermal blanket sample. All other samples did experience discharges when the surface voltage reached -8 to -16 kV. The discharges were photographed. The breakdown voltage for each sample was determined and the average energy lost in the discharge was computed.

Gaseous dielectric mixtures for suppressing carbon formation

Abstract: Carbon formation on voltage breakdown and sparking, and consequent carbon deposits on insulators and other surfaces, is suppressed in dielectric gases of halogenated alkanes by adding SF 6 and/or CO 2 to the halogenated alkane to form a gaseous dielectric mixture. Moreover, certain of the gaseous dielectric mixtures evidence unexpectedly high dielectric breakdown voltages. The gaseous dielectric mixtures are useful in high voltage coaxial lines, in transformers, in minisubstations, and the like.

High voltage driver circuit

Abstract: A semiconductor switching circuit utilizes a relatively low breakdown voltage transistor for switching between a higher and a lower voltage by switching between a first conducting state of said transistor which is a "turned-on" state and a second state which is a "breakdown" state. The switching circuit is especially useful for the operation of display devices.

High-voltage thyristors and diodes made of neutron-irradiated silicon

Abstract: Neutron irradiation is a way to produce homogeneous and well-defined phosphorus doping in large diameter silicon crystals One major application of such silicon is in the field of high-voltage power devices The relation between resistivity and breakdown voltage determined for neutron-irradiated silicon is in good agreement with the theory of Sze and Gibbons It is shown that by changing from conventionally doped silicon to neutron-irradiated silicon noticeable increases in the blocking capability of thyristors can be achieved without an increase of the n-base width Production of power thyristors with blocking voltages of 3 to 5 kV has been successful, indicating that applications of neutron-irradiated silicon have already left the laboratory stage

Polarity Effect on Breakdown Voltage in Organic Liquids

Abstract: The polarity effect on breakdown strength is a well-known phenomenon using a nonuniform electrode system, especially point versus plate electrodes. When the point electrode is negative, particularly, free electrons move in a liquid to form negative ions due to the possibility of electron attachment to electrically neutral atoms or molecules. Negative ions form space charges, by which field stress around the point electrode relaxes. Breakdown voltages have been measured in four liquids having chemical structures differing markedly from each other. It has been found that the breakdown voltage with the point negative is higher than that with the point positive in toluene and n-octhane which have a methyl group in their molecular structure; but there is no such polarity effect in chlorobenzene and carbon tetrachloride which have chlorine atoms. It may be concluded that the polarity effect depends on molecular structure: Electrons attach to methyl groups to make negative ions which may form space charges.