Showing papers on "Capacitance published in 1982"

Mos (Metal Oxide Semiconductor) Physics and Technology

Abstract: Introduction. Field Effect. Metal Oxide Silicon Capacitor at Low Frequencies. Metal Oxide Silicon Capacitor at Intermediate and High Frequencies. Extraction of Interface Trap Properties from the Conductance. Interfacial Nonuniformities. Experimental Evidence for Interface Trap Properties. Extraction of Interface Trap Properties from the Capacitance. Measurement of Silicon Properties. Charges, Barrier Heights, and Flatband Voltage. Charge Trapping in the Oxide. Instrumentation for Measuring Capacitor Characteristics. Oxidation of Silicon--Oxidation Kinetics. Oxidation of Silicon--Technology. Control of Oxide Charges. Models of the Interface. Appendices. Subject Index. Symbol Index.

MOS /metal oxide semiconductor/ physics and technology

Abstract: Introduction. Field Effect. Metal Oxide Silicon Capacitor at Low Frequencies. Metal Oxide Silicon Capacitor at Intermediate and High Frequencies. Extraction of Interface Trap Properties from the Conductance. Interfacial Nonuniformities. Experimental Evidence for Interface Trap Properties. Extraction of Interface Trap Properties from the Capacitance. Measurement of Silicon Properties. Charges, Barrier Heights, and Flatband Voltage. Charge Trapping in the Oxide. Instrumentation for Measuring Capacitor Characteristics. Oxidation of Silicon--Oxidation Kinetics. Oxidation of Silicon--Technology. Control of Oxide Charges. Models of the Interface. Appendices. Subject Index. Symbol Index.

Discrete changes of cell membrane capacitance observed under conditions of enhanced secretion in bovine adrenal chromaffin cells.

Abstract: The capacitance of the surface membrane of small adrenal chromaffin cells was measured with patch-clamp pipettes. Continuous and discrete changes of capacitance were observed. They were interpreted as changes of surface area connected to exocytotic or endocytotic processes. Most of the measurements were performed in the "whole-cell" recording configuration [Hamill, O. P., Marty, A., Neher, E., Sakmann, B. & Sigworth, F. J. (1981) Pflugers Arch. 391, 85-100], which allows the intracellular Ca2+ concentration to be controlled. With an internal solution highly buffered to low values of Ca2+ concentration (10 nM), the surface capacitance usually decreased and could not be markedly changed by electrical stimulation. At low buffering capacity and medium Ca2+ concentrations (0.1-1 microM), the capacitance measurement showed large fluctuations and discrete steps, reflecting both capacitance decrease and increase. A large transient increase of capacitance could be induced by electrical stimulation under these conditions. It was linked to Ca2+ currents through the membrane. Relatively large (2-6 x 10(-14) F) steps of capacitance decrease were common after extensive stimulation. The size distribution of step-like capacitance changes is well compatible with the idea that steps of capacitance increase reflect individual events of exocytosis of chromaffin granules, whereas steps of the opposite polarity reflect the formation of vesicles or vacuoles by endocytosis.

Quantitative measurements of laser-generated acoustic waveforms

Abstract: The generation of acoustic waves in metals by pulsed laser irradiation over a wide range of material conditions has been studied. Capacitance transducers have been used to obtain quantitative measurements of the amplitude of bulk acoustic waveforms where the laser beam was directed onto free metal surfaces in the presence and absence of surface plasmas, and onto modified metal surfaces. The application of acoustic wave propagation theory has allowed theoretical waveforms to be determined. By combining data for thermoelastic and normal force sources, waveforms have been produced that follow closely those measured experimentally.

On the determination of the spatial distribution of deep centers in semiconducting thin films from capacitance transient spectroscopy

Abstract: It is pointed out that a widely used simple formula may give rise to serious errors in profiling deep level concentrations from capacitance transient experiments. A correction formula is derived based on the space‐charge analysis.

A simple model for the overlap capacitance of a VLSI MOS device

Abstract: A simple approximate analytical expression for the overlap capacitance between gate- and source-drain of a VLSI MOS device is derived. The expression takes into account finite polysilicon gate thickness, source-drain junction depth and different dielectric constants of silicon and oxide. A numerical procedure is also described to calculate the exact overlap capacitance with fringing, using the solution of Laplace's equation. A comparison is made to check the accuracy of the analytical expression. Good agreement is found. Experimently obtained gate-source capacitance curves are described. Overlap capacitance and fringing component values derived from these curves are also in good agreement to those predicted by the model.

A simple formula for the estimation of the capacitance of two-dimensional interconnects in VLSI circuits

Abstract: A simple formula for the estimation of the capacitance of a single interconnection line in VLSI circuits is presented It is shown that the approximation agrees favorably with the results obtained from much more costly two-dimensional simulations The approximation is also simpler and more accurate than other approximations that have been proposed

Capacitance-type material level indicator

Abstract: A system and probe for indicating the level of material in a vessel as a function of material capacitance comprising a resonant circuit including a capacitance probe adapted to be disposed in a vessel so as to be responsive to variations in capacitance as a function of material level. An rf oscillator has an output coupled to the resonant circuit and to a phase detector for detecting variations in phase angle as a function of probe capacitance. Level detection circuitry is responsive to an output of the phase detector and to a reference signal indicative of a predetermined level of material for indicating material level as a function of a difference between capacitance at the probe and the reference signal. In the preferred embodiments of the invention disclosed, an automatic calibration circuit adjusts the resonance characteristics of the parallel resonant circuit of the reference signal indicative of a predetermined reference material level.

A MESFET Variable-Capacitance Model for GaAs Integrated Circuit Simulation

Abstract: A simple MESFET capacitance model which has a clearly explained physical meaning for a wide bias voltage range has been developed for use in simulations of GaAs integrated circuits. In this model, gate-source, gate-drain capacitances are represented by analytical expressions which are classified into three different regions for bias voltages: a before-pinch-off region including the neighborhood of the built-in voltage, an after-pinch-off region, a transition region. 2-dimensional analysis results support the validity of the analytically derived capacitance model. The model is applicable to MESFET's used in integrated circuits that have low donor-thickness product.

Equivalent Circuit Analysis of the Impedance Response of Semiconductor/Electrolyte/Counterelectrode Cells

Abstract: A method to determine the equivalent circuit of a semiconductor/electrolyte/counterelectrode cell is presented. The electrical analog of the phenomenon leading to frequency dependent behavior has been taken to be a resistor in series with a capacitor. The case where a large number of RC elements are present has been determined in the following way. The values of the capacitances and time constants of these elements have been assumed to be distributed exponentially. For this distribution it follows that the equivalent circuit can be represented as a frequency dependent resistor in parallel with a frequency dependent capacitor. Expressions for the frequency dependent resistance and capacitance have been derived. The impedance and admittance responses of a large number of circuits have been simulated. The circuit which best represented an n-Fe/sub 2/O/sub 3/ (1% TiO/sub 2/)/1M NaOH/Pt cell was determined by comparing the simulated responses with the measured responses. 18 refs.

Distribution and kinetics of membrane dielectric polarization. II. Frequency domain studies of gating currents.

Abstract: We have studied the admittance of the membrane of squid giant axon under voltage clamp in the absence of ionic conductances in the range of 0-12 kHz for membrane potentials (V) between --130 and 70 mV. The admittance was measured at various holding potentials (HP) or 155 ms after pulsing from a given holding potential. Standard P/4 procedure was used to study gating currents in the same axons. We found that the membrane capacity Cm (omega) is voltage as well as frequency dependent. For any given V, the voltage-dependent part of the membrane capacitance has a maximum as the frequency approaches zero and requires at least a two-time constant equivalent circuit to be described. When the holding potential is varied, the voltage-dependent capacitance follows a bell-shaped curve with a maximum change of 0.15 muF/cm2 at about --60 mV. With the pulse method, the maximum is at --40 mV for HP = --70 and it shifts to --70 mV for HP = 0. The shift in the maximum of the voltage-dependent capacitance is consistent with the shift in the charge (Q) vs. V curve observed in our experiments with regular P/4 procedure when the HP is varied. Our data can be explained qualitatively by a four-state model for the sodium channel gating, where a charged particle can move within the field and interact with another particle not affected by the field.

The shape factor of the capacitance of a conductor

Abstract: This paper shows, analytically and numerically, that the capacitance is a slowly changing function of the conductor shape. This slow change can be monitored by a ‘‘shape factor’’ which is independent of the conductor size. Because of this slow change, from the tabulation of the shape factor, the capacitance of many conductors of arbitrary sizes and shapes with both convex and concave surfaces, can be estimated to an error of 5% or less.

Quadruply self-aligned stacked high-capacitance RAM using Ta 2 O 5 high-density VLSI dynamic memory

Abstract: A new one-transistor, one-capacitor RAM cell structure called a Quadruply Self-Aligned Stacked High Capacitance (QSA SHC) RAM is proposed as a basic cell for a future one-million-bit VLSI memory. This cell consists of a QSA MOSFET and a Ta 2 O 5 capacitor stacked on it. By this cell, the ultimate cell area 3F \times 2F can be realized with sufficient operating margin. Here, F is the minimum feature size. The basic cell was fabricated and its operation was experimentally verified. The leakage current of Ta 2 O 5 film was small enough for the storage capacitor dielectric. Using a 3F \times 4F cell and a 4F pitch sense amplifier, a one-million-bit memory was designed with a 2-µm rule. A cell size of 6.5 × 8 µm2, and a chip size of 9.2 × 9.5 mm2were obtained. The access time, neglecting the RC time constant of the word line, was estimated to be about 170 ns. Based on this design, it is argued that a future one-million-bit memory can be realized by QSA SHC technology with a 2-1-µm process. The mask set of the 1-Mbit RAM was actually fabricated by an electron-beam mask maker. A photomicrograph of the 1-Mbit RAM chip patterned by the mask set is shown. This chip was patterned not to get an operating sample but to show an actual chip image of the future 1- Mbit RAM. The area of each circuit block including storage array can be seen in this chip image.

Pharmacological separation of charge movement components in frog skeletal muscle

Abstract: 1. Charge movements to small 10 mV steps superimposed upon a wide range of closely spaced depolarizing voltage-clamp pulses were studied in frog skeletal muscles under different pharmacological conditions in hypertonic solutions. 2. In control fibres, capacitance was strongly voltage-dependent, especially between potentials of -60 and -20 mV, confirming earlier work. There was a sharp increase in capacitance at around -50 mV. The dependence of non-linear charge on potential was asymmetrical and saturated at around 25 nC/μF. 3. The presence of tetracaine abolished the `hump' in the non-linear transients, which became simple monotonic decays. The dependence of capacitance upon potential was reduced. The maximum available amount of non-linear charge fell to 10 nC/μF. 4. The presence of lidocaine abolished both the `hump' as well as the monotonic part of the non-linear transients. This resulted in capacitance falling with depolarization from -85 mV. 5. Comparing the steady-state properties of the non-linear charge under the different pharmacological conditions made it possible to deduce empirically the following components: (i) A lidocaine-resistant component (qα), which was responsible for the fall in observed capacitance with depolarization from the control voltage. (ii) A component resistant to tetracaine yet abolished by lidocaine (qβ). This possesses quasi-exponential kinetics, and a maximum charge of about 20 nC/μF. (iii) A component abolished by both lidocaine and tetracaine (qγ), which possesses a maximum charge of 15 nC/μF. This has complex kinetics, and its steep dependence upon voltage resembles the potential-dependence of the development of tension in skeletal muscle.

Arrangement for generating DC magnetic fields of alternating polarity for the magnetic-inductive flow measurement

Abstract: An arrangement for generating DC magnetic fields of alternating polarity for the magnetic-inductive flow measurement by means of a field coil which is connected via alternately controlled switching members to a DC voltage source, wherein during the reversal time following the change-over of the switching members a capacitor is connected to the field coil to form a resonant circuit separate from the DC voltage source and the capacitance C of the capacitor in dependence upon the desired reversal time Δt has substantially the value ##EQU1## wherein L is the inductance and R the ohmic resistance of the field coil.

Charge transient spectroscopy

Abstract: A new variation of the deep level transient spectroscopy technique is presented. In the new approach, the current transient is integrated, yielding a charge transient. A simple circuit for integrating the current is given and is analyzed. The charge transient technique is compared to previous capacitance transient and current transient techniques, and the advantages of the new method are discussed. The effects of diode leakage currents are also analyzed. Data are presented for defects in neutron irradiated Si.

Capacitance calculations in MOSFET VLSI

Abstract: A simple empirical relation for the calculation of the capacitance of interconnection lines in MOSFET VLSI, including edge effects, is presented. The equation gives approximate results compared to two-dimensional computer calculations.

Superconducting quantum interference device with very low magnetic flux noise energy

Abstract: We have fabricated dc superconducting quantum interference devices incorporating Josephson tunnel junctions with an inductance of about 2 pH and a capacitance per junction of about 0.3 pF. The lowest measured flux noise energy was 3.2 h/ at 1.4 K at a frequency of 202 kHz. When the 1/f noise was subtracted, the white noise energy decreased from around 3h/ at 4.2 K to below 2h/ at 1.4 K.

Electron tunneling through GaAs grain boundaries

Abstract: Measurements of the zero‐bias dc conductance G0 and high frequency capacitance have been made on GaAs bicrystals doped in the range of 4×1017–2×1018 cm−3. The conductance displays a non‐Arrhenius temperature dependence with high temperature values of ∂(ln G0)/∂(1/kT) less than the barrier heights deduced from the capacitance. Theoretical calculations of transbarrier currents using the unified approach of Fonash show that thermally assisted tunneling currents are important.

A corrugated capacitor cell (CCC) for megabit dynamic MOS memories

Abstract: A new dRAM cell named "CCC" (Corrugated Capacitor Cell) has been successfully developed based on the one-device cell concept. This CCC is characterized by an etched-moat storage-capacitor extended into the substrate, resulting in an almost independent increase in storage capacitance without cell size enlargement. A typical value of 45 fF has been obtained with 4 × 8 µm2CCC having a 2.5-µm deep moat and a capacitor insulator equivalent to 15 nm SiO 2 in thickness. A signal of 200 mV is realized in 32 kbit dRAM operation with a folded-bit line arrangement having 128 bit identical CCC's. The CCC concept is promising for generations of 1 Mbit dRAM's and beyond.

Transparent capacitance membrane switch

Abstract: A more transparent capacitance membrane switch in which capacitance elements are offset from their associated switch locations so as to be out of the transparent field of view through the switch.

Energy dependence of electron-capture cross section of gap states in n -type a -Si:H

Abstract: Isothermal capacitance transient spectroscopy has been employed for the measurement of the capture cross section of continuously distributed trap levels in $a$-Si:H, and the energy dependence of the electron-capture cross section of gap states has been determined for the first time. Experimental results indicate that an electron-capture cross section of a localized level decreases exponentially with an energy depth measured from the mobility edge of the conduction band, suggesting that the multiphonon emission predominates in the electron-capture process at the deep gap states in $a$-Si:H.

Determination of surface space–charge capacitance using a light probe

Abstract: A new technique for the characterization of semiconductors, surface photovoltage measured capacitance (SPMC) is introduced. This technique permits the semiconductor surface space‐charge capacitance to be determined by simple measurements of the intrinsic surface photovoltage (ISPV) induced by chopped light. ISPV transients for a semiconductor under depletion conditions are discussed. Both theoretical and experimental results are presented demonstrating the existence of two limiting dependences of the ISPV on the ratio Φ/f (photon flux divided by the chopping frequency of the incident light). It is shown that ISPV induced by low‐intensity, high‐frequency chopped light is proportional to the reciprocal of the semiconductor surface space‐charge capacitance. This dependence is fundamental to the SPMC method whose capabilities are illustrated using GaAs. Using a three‐electrode electrochemical cell, the doping concentration, the flat band potential and the energy of surface states which are responsible for the...

On the Superposition of Inductive and Capacitive Coupling in Crosstalk-Prediction Models

Abstract: An examination of traditional low-frequency crosstalk-prediction models is presented. From the exact solution of the transmission-line equations for a 3-conductor line, it is shown that superimposing crosstalk contributions due to mutual inductance and mutual capacitance between the two circuits is valid for a sufficiently small frequency. The widely held notion that one may superimpose the effects of both mutual and self elements ( inductance and capacitance) is shown to be incorrect.

Electrical and optical characteristics of a schottky barrier on a cleaved surface of the layered semiconductor InSe

Abstract: Forward current-voltage characteristics at various temperatures and the frequency depencence of barrier capacitance in Au/InSe Schottky barrier diodes are investigated in detail. The origin of an excess temperature T0 and the effect of electron traps on the barrier capacitance are discussed. Strom-Spannungscharakteristiken bei verschiedenen Temperaturen und die Frequenzabhangigkeit der Sperrschicht-Kapazitat von Au/InSe-Schottky-Dioden werden ausfuhrlich untersucht. Die Ursache der Rest-Temperatur T0 und der Einflus der Elektronenhaftstellen auf die Sperrschicht-Kapazitat werden diskutiert.

High-frequency characteristics of GaAlAs injection lasers

Abstract: This paper discusses the results of an extensive experimental study of the high-frequency characteristics of several commercial (GaAl)As injection lasers. The lasers tested included the Hitachi buried heterostructure (BH), the Hitachi channel substrate planar (CSP), the Mitsubishi transverse junction stripe (TJS), the General Optronics stripe (GO), and the RCA constricted double heterostructure (CDH). We find that the maximum practical analog modulation frequency f o is in the range of 5 GHz. This practical modulation frequency is limited by a combination of laser-relaxation resonance, laser parasitics, and drive current necessary for long-life operation. The relationship between laser-relaxation oscillation resonance frequency f o and drive current can be expressed as f_{o} = K(I/Ith - 1)^{1/2} GHz where I and Ith are the laser drive and threshold currents, respectively. The value of K is experimentally determined to lie in the range 3.0 K j and a capacitance C j . The product of R_{j}C_{j} has been experimentally determined for both the Hitachi CSP and BH laser and lies in the range of 1-1.1 \times 10^{-10} s. The effect of laser mount and packaging can also be included in the equivalent circuit by the addition of series inductors and shunt capacitors. Lastly, all injection lasers studied displayed a dip in the small signal modulation response prior to the onset of the relaxation oscillation resonance. In particular, there is a pronounced dip even for lasers with good lateral carrier confinement at dc, such as the buried heretostructure (BH). Previous workers have attributed the dip in the modulation response as resulting from either lateral diffusion of injected carriers, or the effect of junction capacitance. Our experimental results indicate that while the effect of the junction capacitance may play some role in explaining the dip for the BH laser, it is not the dominant mechanism. We speculate that lasers with good lateral carrier confinement at dc (BH) may suffer a significant degradation of carrier confinement at gigahertz rates. A simple qualitative model is proposed to explain this mechanism and methods for reducing the effect are discussed.