Showing papers on "Leakage (electronics) published in 1983"

Total Dose Effects in Recessed Oxide Digital Bipolar Microcircuits

Abstract: Total dose failure levels in digital bipolar microcircuits utilizing recessed oxides were measured at levels as low as 5 Krad(Si). Typical failure levels are in the 10-100 Krad(Si) range. Failure was found to be a strong function of irradiation bias and annealing time after irradiation. In addition, total dose "windows" below 100 Krad(Si) were observed. The radiation failure mechanism is predominantly inversion of p type silicon either at the bottom of the recessed field oxide, causing buried layer to buried layer channeling, or on the oxide sidewall causing collector to emitter leakage. In addition, a failure mode due to increased sidewall current was observed in a nonisolated form of integrated injection logic. Hardening approaches have been identified and investigated at several manufacturers. Device failure levels were found to vary by several orders of magnitude depending on process lot and layout revision.

Quantitative assessment of postsurgical breakdown of the blood-aqueous barrier.

Abstract: • Breakdown and reestablishment of the blood-aqueous barrier (BAB) following experimental surgical trauma was evaluated by anterior segment slitlamp fluorophotometry. Substantially more fluorescein leakage was caused by 6-mm limbal incisions for at least the first four postoperative days than was produced by 3-mm incisions. Following 3-mm corneal incisions, leakage of fluorescein closely paralleled that of fluorescein-labeled dextran 70 (molecular weight, 70,000) for the first three postoperative days. On the fourth postoperative day, the BAB appeared reestablished to fluorescein-labeled dextran 70 but was still abnormally permeable to fluorescein. Thus, it appears that although fluorescein is the most sensitive technique of demonstrating breakdown of BAB, it may not always be an indicator of large-molecule permeability.

CMOS on buried nitride—A VLSI SOI technology

Abstract: A CMOS technology in silicon on insulator (SOI) for VLSI applications is presented. The insulator is a buried silicon nitride formed by nitrogen implantation and annealing. The CMOS devices are fabricated in the superficial monocrystalline silicon layer without an epitaxial process, 1-µm PMOS and 2-µm NMOS transistors have been realized, which have been used to built inverters, ring Oscillators, and other circuits. With 40-nm gate oxide the transistors withstand gate and drain voltages of 10 V. Mobilities, subthreshold behavior, and leakage currents are nearly the same as in bulk-CMOS devices. Ring-oscillator measurements yield inverter delay times of 230 ps and power delay products of 14 fJ.

Carrier leakage and temperature dependence of InGaAsP lasers

Abstract: A direct measurement of electron and hole leakage in InGaAsP/InP lasers has been carried out. The effect of electron leakage on the temperature sensitivity of InGaAsP/InP lasers has been revealed.

High voltage insulators

Abstract: A method of manufacturing an improved electrical high voltage coated insulator is described. The method involves applying and curing a one-part, room temperature curable silicone composition to the surface of an insulator, the insulator surface having a minimum designated arc resistance. The silicone composition is the product obtained by mixing in the substantial absence of moisture a specified polydimethylsiloxane fluid containing hydroxyl radicals, finely divided aluminum hydroxide filler, a silane of the formula R b Si(ON═X) 4-b and an optional condensation catalyst. The coating cures on exposure to atmospheric moisture to produce a surface adhered onto the insulator that resists the development of leakage currents and flashover failure upon exposure to electrical stress, moisture, contamination, and other outdoor weathering stresses.

A Technique for Calculating Shunt Leakage and Cell Currents in Bipolar Stacks Having Divided or Undivided Cells

Abstract: The present investigation has the objective to develop a compact procedure for calculating current distributions in cell assemblies with parallel electrolyte feed. Ionic shunt or bypass currents short-circuit each cell in the assembly causing power loss, corrosion, current inefficiency, and nonuniform cell-to-cell current distribution. The magnitude of the bypass current in an assembly is a function of the number of cells in the assembly, cell voltage, conductivity of the electrolyte, and the geometry of the electrolyte feed system. The reported study presents a treatment of bypass current based on the solution of finite difference equations. The formalism is applied to assemblies of divided and undivided cells. The analysis yields a set of compact equations for determining branch currents in the circuit analog.

Increased avalanche breakdown voltage and controlled surface electric fields using a junction termination extension (JTE) technique

Abstract: Extremely high breakdown voltages with very low leakage current have been achieved in plane and planar p-n junctions by using an ion-implemented junction extension for precise control of the depletion region charge in the junction termination. A theory is presented which shows a greatly improved control of both the peak surface and bulk electric fields in reverse biased p-n junctions. Experimental results show breakdown voltages greater than 95 percent of the ideal breakdown voltage with lower leakage currents than corresponding unimplanted devices. As an example, diodes with a normal breakdown voltage of 1050 V and a 0.5 mA leakage current become 1400 V (1450 ideal) devices with a 5 µA leakage current. Applications of the junction termination technique is feasible in MOS technology, but is more attractive in power devices where reduced surface fields are as important as the extremely high breakdown voltages. Reduced surface fields allow more flexibility in passivation techniques, two of which we have used to date. Our results also show that the implant can be activated at a variety of temperatures with a good degree of success; process flexibility being the goal of these tests.

3-D finite element predictions of magnetostatic leakage fields

Abstract: Traditionally electromagnetic leakage fields have largely been of interest to the designers of electrical machinery and magnetic tape heads. An increasingly important application of such leakage fields, however, relates to their use as a mechanism for the detection of defects in ferromagnetic materials. The finite element simulation of three-dimensional active leakage fields is described, and the theoretical predictions are compared with experimentally obtained leakage field profiles for a rectangular slot in a carbon steel bar. Particular emphasis is placed on techniques for determining boundary conditions and the appropriate excitation current distribution in the bar.

Impact of silicon substrates on leakage currents

Abstract: Leakage currents of n+-p-diodes, made on four different groups of p-type silicon substrates, are investigated at temperatures between 50 and 120°C. At these temperatures, diffusion of thermally generated minority carriers from the bulk is the dominant leakage current mechanism and determines the holding time of dynamic memories. Measurements at these temperatures show that for Czochral-sky-grown wafers (CZ) with a high interstitial oxygen concentration as is used for intrinsic gettering, the leakage current densities are about 1O× higher than for CZ wafers with a low oxygen concentration or floating-zone wafers (FZ), and are about 100× higher than for p-p+-epitaxial substrates. Simple analytical formulas explaining these large differences will be presented. Finally a short discussion about the optimum substrate for future high-density memories will be given.

Switched capacitor circuit with high power supply projection ratio

Abstract: In a switched capacitor circuit, in order to eliminate leakage of a power supply noise component to a signal line through an input capacitance of an operation amplifier, (1) an operating current of at least a first, differential stage among stages of the operational amplifier is regulated by a current regulation bias circuit, and (2) a power supply noise component having the same phase as that of an input signal is applied to the gate of a transistor of a gain stage, thereby stabilizing the operating point. In order to eliminate leakage of the power supply noise component to the signal line through a parasitic capacitance of an analog switch, (3) a dummy switch is used to detect a signal corresponding to the leakage component of the power supply noise component to the signal line, and an inverted signal having the opposite phase to that of the signal corresponding to the leakage component is applied to a substrate of the analog switch, thereby cancelling the actual leakage component.

Heterojunction semiconductor device

Abstract: A semiconductor device is described for sensing radiant energy incorporating a pn junction formed by two layers of materials each having a different energy band gap to form a heterojunction diode and wherein the layer having the greatest energy band gap fully covers the boundaries or perimeter of the layer having a lesser energy band gap to reduce surface leakage current. Further, a semiconductor device is described for sensing radiant energy incorporating a pn junction formed by two layers of materials each having a different energy band gap to form a heterojunction diode wherein the layer having the greatest energy band gap has spaced-apart P regions to form the anode of the heterojunction diode whereby the heterojunction diode is buried below the surface of the layer having the greatest energy band gap. The invention reduces the problem of surface and bulk leakage across heterojunction diodes.

A simple punchthrough model for short-channel MOSFET's

Abstract: Punchthrough currents impose severe limitations on the minimum channel length and leakage currents of scaled MOS transistors. A simple model is proposed to calculate the low-level punchthrough characteristics. Taking into account the two-dimensional geometrical effects, this model calculates the drain-induced barrier-lowering (DIBL) and the punchthrough current as a function of the processing parameters, and the gate, drain, and substrate bias. Experiments on devices with substrate dopings 6 × 1014and 6.6 × 1015cm-3and channel lengths from 1 to 2 µm show good agreement with the theory.

A dynamic RAM Cell in recrystallized polysilicon

Abstract: A new, one-transistor, dynamic RAM cell has been fabricated in beam-recrystallized polysilicon. Placing thin oxides both above and below the storage region doubles the storage capacitance. Complete isolation of the storage region by oxides also reduces the susceptibility of the cell to soft errors from collection of charge injected into the substrate by the surrounding elements or by alpha particles. Long storage times are feasible, being limited only by the leakage of the access transistor. A thick oxide under the bit line reduces the bit-line capacitance, further increasing the ratio of storage capacitance to bit-line capacitance.

Investigation of the Tip Clearance Flow Inside and at the Exit of a Compressor Rotor Passage—Part I: Mean Velocity Field

Abstract: A stationary two-sensor hot-wire probe has been used in combination with an ensemble averaging technique to measure the flow in the tip clearance region of a compressor rotor with emphasis on the leakage flow development inside the tip-clearance region and at the exit of the rotor. It is found that the presence and interaction of leakage flow, annulus boundary layer, and the scraping vortex is the dominant feature at mid-chord position. The rotation of the blade augments the leakage flow, resulting in the movement of the leakage jet toward the mid-passage. The blade-to-blade distribution of properties is shown to be highly nonuniform, except in the downstream and upstream regions.

Amplifier circuit free from leakage between input and output ports

Abstract: A leakage current between the inverting input terminal and the output terminal of an operational amplifier having a switch between the two terminals is prevented from flowing by equalizing the potentials at the two terminals of the switch when it is open. This is accomplished by dividing the switch into two and inserting an additional switch between the intermediate node of the divided two switches and a reference potential point.

Residual charge on a switched capacitor [MOS type]

Abstract: A simple semiempirical model is presented to estimate the residual charge (feedthrough error) on a switched MOS capacitor. The model ignores the complexities of changing channel resistance during the turnoff transient, treating the channel as a simple on/off switch. In spite of this simplification, the results agree with computer simulations over a wide range of parameters. The model is easily extended to more complex situations found in typical switched-capacitor circuits.

Production of flux cored wire

Abstract: PURPOSE:To improve the quality of a flux cored wire for welding in the stage of forming a band steel to a tubular shape, packing a flux therein, welding both ends of the band steel and producing said wire, by limiting the content of oxygen in the band steel and setting the area of wled metal in the tubular section at a specific value. CONSTITUTION:A band steel 2 of 8-100ppm content of oxygen is formed successively to a tubular shape with working rolls as shown by (a), (b), (c), and a flux F is packed therein from a hopper 3. The butted two end parts are sealed by TIG welding W. The tube is then passed through dies 4-1, 4-2, 4-3 and is drawn to a prescribed size, whereby a flux cored wire is produced. The weld heat input during the welding in this case is regulated and the wire is so welded that the sectional area ratio of weld metal with respect to the sectional area in the tubular metallic part of the wire attains 5-25%. Defects such as wetting of the flux occuring in the lack of the sealing property in the weld zone, and the leakage of the flux are prevented.

Photon generation in forward-biased silicon p-n junctions

Abstract: Photons are generated by forward biasing a silicon p-n junction at 10-5∼ 10-4quantum efficiency through radiative recombination. At large distances from the forward-biased junction, leakage currents of magnitudes significant for some VLSI circuits can appear due to the substrate minority carriers generated by the photons. The effective decay length of the measured leakage current is about several hundred to one thousand micrometers. The effects of forward biasing an input node or a parasitic lateral bipolar transistor are, therefore, longer ranged than commonly assumed.

Schottky-barrier mos devices

Abstract: Schottky-barrier MOS and CMOS devices are significantly improved by selectively doping the regions surrounding the Schottky-barrier source and drain contacts. For p-channel devices, acceptor doping is carried out in either a one-step or a two-step ion implantation procedure. For n-channel devices, donor doping is carried out in a two-step procedure. In each case, current injection into the channel is enhanced and leakage to the substrate is reduced while still maintaining substantial immunity to parasitic bipolar transistor action (MOS devices) and to latchup (CMOS devices).

Charge pumping circuit

Abstract: A substrate voltage generator is disclosed which provides over 1.5 times as much current for a given size circuit, as has been capable with prior art substrate voltage generators. This is achieved by means of a high capacitance per unit area charge pumping capacitor having a triple plate structure and further through the space saving technique of providing a dual use for the source diffusion of the current sinking device in the circuit so as to also serve as the guard ring around the charge pumping circuit of the substrate voltage generator. These and other features of the substrate voltage generator circuit enable relatively large quantities of current to be supplied for maintaining the substrate voltage in large dimension VLSI chips having significant diffusion leakage currents.

Reduction of Magnetic Flux Leakage from an Induction Heating Range

Abstract: In the basic arrangement for an induction heating range consisting of an exciting coil and a cooking vessel, magnetic flux leakage always exists which should be reduced to avoid various harmful effects in practical use. It was found that a cylindrical conducting ring which was set to surround the exciting coil was much more effective for the reduction of the flux leakage than the conventional wire ring. The position and width of the ring were adjusted to give the best reduction effect of flux leakage. The validity of the cylindrical ring was confirmed theoretically by the field analysis based upon the finite element method newly developed to model exterior open regions satisfactorily.

Apparatus for measuring and displaying leakage rates in a tracer gas leakage detector

Abstract: A tracer gas leakage detector mainly comprises a primary vacuum pump which is selectably connectable to a unit to be tested for leakage, an inlet valve also connectable to the unit to be tested and communicating with a measurement cell capable of being evacuated by a primary pump and a secondary pump. The inlet valve includes a motor-controlled valve member to enable the aperture through the inlet valve to be servo-controlled to the inlet pressure of the measurement cell, and conversion means providing an electrical signal representative of the aperture. The apparatus for measuring and displaying the leakage flow rate is connected to receive the aperture size representing electrical signal and includes a display system for displaying, as a function of the aperture size representing electrical signal, a valid sub-range of n decades of possible valid measurements taken from a total measuring range of N decades for the apparatus as a whole, thereby warning users that any indicated leakage flow rate values outside the valid sub-range are spurious. The N decades may be marked on a band (22) which is movable relative to a window (24). A pointer (25) is also movable relative to the window. A reading is valid if the pointer lies in the window.

Oil Leakage and Friction Forces of Reciprocating O-Ring Seals Considering Cavitation

Abstract: The problem of calculating oil film thicknesses, oil leakage and friction forces in seal situations like those occurring in hydraulic cylinders is considered. A general scheme for the analysis is p ...

Field and hot carrier enhanced leakage in InGaAsP/InP heterojunctions

Abstract: A model calculation for the field and hot carrier enhanced electron leakage in InGaAsP/InP LED's and lasers is presented. The significant influence of the doping level in the P-InP confining layer on leakage current is confirmed.

Fluid leak testing method

Abstract: A method for testing leakage from an element, such as a container. The element to be tested is sealed within an enclosure so as to define a reduced volume space in the enclosure around the container. An increase in the pressure in the surrounding space is detected as a function of the amount of leakage of high pressure fluid from the container to that space. Reduced temperature sensitivity is effected by reducing the pressure in the space. However, the device functions to improve sensitivity where the space is provided at ambient pressure at the start of the test cycle, as well. The apparatus may include a control for effecting the leakage testing automatically and indicating to the user the result of the testing as desired.