Showing papers on "Equivalent series resistance published in 1991"

Performance of gain-guided surface emitting lasers with semiconductor distributed Bragg reflectors

Abstract: The performance limitations of gain-guided vertical cavity surface emitting lasers (VCSELs) which use epitaxially grown semiconductor distributed Bragg reflectors (DBRs) are discussed. The light-current (L-I) characteristics and emission wavelength of such lasers are examined as a function of temperature and time under continuous wave (CW) and pulsed operation. The authors observed a sharp roll-over in the CW L-I characteristics which limits the maximum output power. The threshold current under CW operation is found to be lower than that obtained under pulsed conditions. Several microseconds long delay in lasing turn-on is also observed. It is shown quantitatively that these anomalies are a consequence of severe heating effects. It is shown that reduction of the series resistance and threshold current density can lead to significant improvements in the power performance of VCSELs. >

Low series resistance high-efficiency GaAs/AlGaAs vertical-cavity surface-emitting lasers with continuously graded mirrors grown by MOCVD

Abstract: GaAs/AlGaAs vertical-cavity top-surface-emitting lasers (VCSELs) with a continuously graded mirror composition have been grown by MOCVD, and planar devices with proton-implant current confinement have been characterized. Continuous grading of the heterointerfaces in the Bragg reflectors eliminated the energy-band discontinuities, thus improving carrier transport and resulting in a substantial reduction in the series resistance and threshold voltage of the laser diodes. These VCSELs have excellent room-temperature CW electrical characteristics, including some of the lowest series resistances, highest power efficiencies and lowest operating voltages ever reported. >

Analysis of the inductance and the stray capacitance of the dry-etched micro inductors

Abstract: Thin film inductors with meander coils or spiral coils were examined systematically. The minimum line spacing of the inductors was 1.5 mu m. In case of air core inductors, both inductance and stray capacitance were calculated from the dimension of the inductors, and they agreed well with measured values. With the application of a magnetic thin film, the inductance is increased and the degree of increase was proportional to the length of the coil. It is found that the capacitance between conductor and magnetic film is very significant and needs special consideration. >

Class D current-driven rectifiers for resonant DC/DC converter applications

Abstract: Analyses and experimental results are given for a family of three Class D current-driven rectifiers. The diode current is half-sine wave and the diode voltage is a square wave. The diode forward voltage and forward resistance are taken into account in the analyses. The basic performance parameters of the rectifiers are determined, such as input resistance, voltage transfer function, efficiency, and power factor. The ripple voltage is estimated, and some effects of the equivalent series resistance and equivalent series inductance of filter capacitors on the ripples are discussed. The experimental results were obtained using IR31DQ06 Schottky diodes at 1 MHz and 16 W output power. >

Vertical cavity surface emitting laser with lateral injection

Abstract: A planar semiconductor laser having low thermal and series resistance is fabricated. The semiconductor laser has an optical waveguide and a lateral current injection path provided by a conductive region. The conductive region disorders the active region and the first 1/4 wave stack of the laser, which reduces the reflectivity, therefore allowing control of the optical waveguide independent of the current flow. By forming the conductive region, the laser of the present invention can have stable optical characteristics and a bigger emission spot due to the weak built-in waveguide, thus resulting in the formation of a device having high output and a low thermal and series resistance.

Pulse withstand capability of self-healing metalized polypropylene capacitors in power applications

Abstract: Experiments performed on the end-edge contacts of polypropylene capacitors to determine whether the thermal effect is the main cause of their degradation are described. Current pulses with different wave-shapes but with the same value of the Joule integral were applied to the contacts, and the degradation levels were ascertained by measuring the tan delta variation, since degradation of the contacts results in an increase of the equivalent series resistance of the capacitor. The results obtained show only a partial dependence of the degradation level on thermal stress, revealing a contribution from the electrical and mechanical stresses. >

Transverse Mode Characteristics of a DBR-Surface Emitting Laser with Buried Heterostructure

Abstract: Distributed Bragg reflector (DBR)-surface emitting lasers (SELs) with buried heterostructure (BH) are fabricated with the combination of metal-organic chemical vapor deposition (MOCVD), electron cyclotron resonance (ECR) dry-etching and liquid phase epitaxial (LPE) regrowth techniques. Low threshold and stable fundamental lateral-mode characteristics are realized by the optimum design of the cavity diameter and refractive indices. Other important characteristics such as polarization characteristics, series resistance and thermal resistance are also discussed.

An eight-terminal Kelvin-tapped bipolar transistor for extracting parasitic series resistances

Abstract: A novel DC method for determining the components of series resistance in bipolar transistors is presented. As a DC technique, it shows unprecedented accuracy as demonstrated by its application to both metal-contacted heterojunction transistors and more conventional bipolar junction transistors (BJTs). The measurement error was minimized by using a single double-base Kelvin-tapped transistor to extract all components of series resistance. This extraction technique was applied to transistors from an industrial poly-contacted BJT process with various geometries. The authors describe the theory and application of this extraction technique in both its simplified form, where the emitter resistance is assumed to be lumped and bias-independent, and in its more general form, where it includes the distributed nature of both the emitter and the intrinsic base resistances. An exact expression for the DC and AC bias-dependent intrinsic base resistance and a methodology for calculating effective resistances for bipolar devices are presented. >

Performance analysis of a solar array under shadow condition

Abstract: The investigation deals with performance studies of a solar array consisting of two modules, each having 25 cells in series. The load characteristics of the array are studied experimentally and it is observed that, as the shadowed area increases, the overall performance of the array is significantly degraded. Theoretical analysis of such an array has also been carried out to explore the possible mechanisms responsible for array degradation. In the analysis, we consider an additional series resistance for the dark region, whereas earlier workers have overestimated the contribution of the dark region because they have always taken into account identical series resistances for the illuminated, as well as the dark, region. Simulation of the enhanced series resistance of the dark region in the present work has been done by the effective surface resistance of the emitter layer caused by a metallic grid, because of the biasing of the dark region by the illuminated area. Under such biasing, the dark region acts as a load on the illuminated region and causes a loss of current. This is simulated by an additional series resistance (Rsurf). The analysis, which is based on consideration of the enhanced series resistance of the dark region, produces a better match between experimental and theoretical results.

Effect of operating electric power on the dynamic behavior of quantum well vertical‐cavity surface‐emitting lasers

Abstract: We investigated the effect of high operating voltage and series resistance on the dynamic behavior of strained InGaAs/GaAs quantum well vertical‐cavity surface‐emitting lasers (VCSELs). A large wavelength chirp in the lasing spectrum is observed for the lasers with high voltage/resistance even under low‐duty‐cycle pulse operation due to resistive heating close to the laser junction. Using an optimized laser design, VCSELs with 2.6 V threshold voltage and 40 Ω resistance are achieved. We believe this is the lowest threshold voltage and resistance reported to date for a 20 μm VCSEL with as‐grown mirrors. The wavelength chirp is reduced by nearly two orders of magnitude for these improved lasers.

Fabrication of Vertical-Cavity Front-Surface-Emitting Laser Diode (FSELD) Using a Heterojunction Bipolar Transistor Process

Abstract: We have investigated a front-surface-emitting laser diode (FSELD) which has both the n and p electrodes on the top surface and emits laser light from the front surface of the wafer. Since its structure is similar to that of HBT, it was fabricated using the conventional HBT process and mask sets. The current flows bypassing the high-series-resistance DBR stacks, and the active layer is surrounded by an oxygen-implanted semi-insulating layer. It showed a low series resistance and low threshold current of 6 mA, for a 25 µm-diameter laser.

An improved analytical LDD-MOSFET model for digital and analog circuit simulation for all channel lengths down to deep-submicron

Abstract: An improved analytical LDD (lightly doped drain)-MOSFET model for digital and analog circuit simulation in the deep-submicron region is described This model includes all short and narrow channel effects and a substrate current model Special emphasis was placed on the voltage-dependent effective channel length and series resistance of LDD devices The voltage-dependent channel length and series resistance of LDD devices are measured electrically, verified with capacitance measurements, and introduced into the model >

Energy transmission of switched-capacitor circuit and application to dc-dc converter

Abstract: The switched capacitor (SC) circuit has been applied to analog signal processing, but few reports have been made on the application to power circuit. Recently, a report has been made on the dc-dc converter using the SC circuit, but the circuit still has a number of problems, e.g., the loss due to the switching element or equivalent resistance of the SC circuit, the output ripple and the noise. From such a viewpoint, this paper presents first the theoretical and experimental investigations on the energy loss, energy transmission efficiency and output power of the dc-dc converter using the basic SC circuit. Based on that result, dc-dc converters are considered using a series-parallel switching SC circuit with more than one capacitor. It is seen as a result that the loss due to the equivalent resistance is inevitable, even if ideal switching elements or capacitors are used in those SC circuits. As a means to cope with this problem, the dc-dc converter using a new SC circuit is proposed, where the zero-voltage switching mechanism is employed using a high-frequency supply and the peak-detector circuit. It is shown theoretically that the loss due to the equivalent resistance is not produced in principle in the proposed SC circuit. A result of experiment is shown with a drastic improvement.

SPICE modeling of cascade solar cells

Abstract: An equivalent circuit representing a two-junction cascade solar cell is presented. The solar cell diode equations are applied. Terms for the light-generated currents, diffusion currents, space charge recombination currents, series and shunt resistance, the resistance for the window layer and the substrate, and the equivalent resistance for the tunnel diode are included. An AlGaAs/GaAs cascade solar cell is considered as an example. SPICE was used to simulate the cascade solar cell for the following: the cascade solar cell I-V curve with temperature as a parameter, the cascade cell P-V curves with temperature as a parameter, open-circuit voltage of the cascade cell versus temperature, and fill factor of the cascade cell versus temperature. The results of this SPICE simulation compared favorably with the data available in the published literature. >

Silicon avalanche cathodes and their characteristics

Abstract: A highly doped shallow p-n junction (

A new PSPICE sub-circuit for the power MOSFET featuring global temperature options

Abstract: An empirical sub-circuit implemented in PSPICE is presented. It accurately portrays the vertical DMOS power MOSFET electrical and thermal responses. Excellent agreement is demonstrated between measured and modeled responses, including first and third quadrant MOSFET and gate charge behavior, body diode effects, breakdown voltage at high and low currents, gate equivalent series resistance, and package inductances for temperatures between -55 degrees C and 175 degrees C. Parameter extraction is relatively straightforward, as described. >

High frequency performance of capacitors

Abstract: The high-frequency performance of capacitors is related to their geometry and material properties. By considering multilayer capacitors as distributed electrical systems, the tools of ICONSIM are applied to study resonant frequencies, equivalent circuits of capacitors, and the influence of ground planes, test fixtures, and type of connection topology. The methods established are applied to well-documented capacitors described in the literature and good agreement between experimental results and analyses is obtained. >

Planar 100 GHz Silicon Detector Circuits

Abstract: On high resistive silicon substrates Schottky barrier diodes have been monolithically integrated with planar antenna structures. The Schottky barrier diodes were fabricated on n+ diffusion regions with thin epitaxial layers grown by molecular beam epitaxy. Low series resistance (≪ 6 ?), ideality factor of less than 1.1 and cut-off frequencies up to 1 THz have been achieved. The maximum sensitivity of the detector-was 90 mV/(mW cm?2) at 94 GHz.

Ohmic heating and series resistance of a vertical‐microcavity surface‐emitting laser

Abstract: We report the results of investigations on the transient heating and series resistance of a vertical‐microcavity surface‐emitting (VMSE) laser with an air‐bridge structure. Transient temperature broadening of the lasing spectrum and chirping of the current versus voltage characteristic are analyzed experimentally and theoretically. We believe that the experiments provide us valuable information on the severity of the heating problems in VMSE laser.

Optimum electrical PD test method for large capacitors

Abstract: The optimum method for electrical partial discharge testing of large capacitors, including the effects of internal inductance, is determined. The results indicate that internal inductance does not adversely affect detection sensitivity if the detection impedance is made equal to the critical damping resistance. This has the advantage of providing a nonresonant waveform which can be detected in a near-optimum manner using a simple low-pass filter. >

Salicided source/drain considerations on UTF SIMOX

Abstract: Integration of the salicide process with ultrathin film (UFT) SOI (silicon-on-insulator) requires consideration of concerns relating to the limited amount of silicon in the source/drain regions. With improper source/drain doping strategies a resistive Schottky diode characteristic may result, providing severely limited gate drive. This effect can be modeled in PISCES-2B. Comparisons between hardware and simulation on salicided and nonsalicided devices are presented along with a variety of source/drain designs intended to avoid the formation of this device series resistance component. Analysis of the simulations indicated that the series resistance is caused by current crowding at the source edge, since the Schottky diode is reverse-biased and unable to participate in electron injection. This problem becomes more severe at reduced silicon thicknesses. >

Design considerations for high-frequency crystal oscillators

Abstract: The deleterious effects of crystal shunt capacitance and series resistance on the performance of series-mode oscillators are discussed. When the parasitic capacitance across the crystal significantly modifies the transconductance of the amplifying stage the circuits can become susceptible to a parasitic second mode of oscillation above the series-resonance frequency of the crystal. A simple model that can sufficiently describe such crystal oscillator circuits was developed and used to derive simple design equations that can accurately predict the behavior of these circuits. The design equations should be especially useful for a reliable design in cases when it is not practical to use an additional inductor to compensate for the parasitic shunt capacitance of the crystal. It is shown theoretically that the inclusion of this capacitance in the feedback path reduces the total effective capacitance in the tank circuit, which is tuned to the desired overtone frequency. This creates a second mode of oscillation frequency which is higher than the desired crystal resonance frequency. The ranges of loop-gain and tank resistance values that can prevent this parasitic mode of oscillations are derived. It is also shown that the useful loop gain for the desired oscillations to start is restricted to a similar region by the crystal shunt capacitance and series resistance. >

Determination of the gate-voltage dependent series resistance and channel length in sub micron LDD-MOSFETs

Abstract: In short channel MOSFETs the effects of series resistance become increasingly important. In this paper the limitations of two existing series resistance measurement methods [1,2] will be discussed. Because of their limitations a new measurement method will be presented for the determination of the gate voltage dependent series resistance. In addition a very useful numerical process and device simulation method to estimate the source (drain) series resistance under several bias conditions will be discussed.

Resonant technique and apparatus for thermal capacitor screening

Abstract: A method and system for driving a plurality of transient decoupling capacitors connected in a circuit in order to heat them and to screen them via a thermal image of them. Radio-frequency excitation is provided for the purpose by connecting a pulse driver through an inductive circuit and a series capacitance to supply a driving current to the decoupling capacitors. The inductance is selected to yield resonance at a selected frequency; and the series capacitance provides a voltage divider to help set the frequency and to adjust the level of the drive of the decoupling capacitors.

Evaluation of electrolytic capacitors for high peak current pulse duty

Abstract: A new type of electrolytic capacitor has been developed specifically for high-peak-current applications. Preliminary results of an ongoing research effort to determine the operational characteristics of this new type of electrolytic capacitor are reported. The new electrolytic capacitors, designed for pulse discharge application, were tested in a low-inductance discharge circuit to evaluate the maximum current extractable, internal inductance of the capacitors (equivalent series inductance), internal losses of the capacitor (equivalent series resistance), and the potential lifetimes of the capacitors. The peak currents extracted ranged from 17 kA for the 2000- mu F unit to 27 kA for the 6800- mu F unit, with pulsewidths ranging from approximately 100 to 280 mu s for the 2000- and 6800- mu F units, respectively. >

Adjusting method of equivalent series resistance of ceramic capacitor

Abstract: PURPOSE: To provide method to adjust the equivalent series resistance of a ceramic capacitor with which it is possible to obtain higher equivalent series resistance value. CONSTITUTION: A metal oxide film 14 is formed on the surface of an outside electrode 13 conducting to the inside electrodes 11a, 11b with heating treatment, for example, and the equivalent series resistance value is adjusted by altering the thickness of the film of the metal oxide film 14 by way of grinding or charging the temperature of heat-treatment, for example. It is possible to easily remove the fluctuation of the low frequency that is superimposed to the power supply line by using a small-sized ceramic capacitor and to make the unit small. Further, it is possible to easily adjust the equivalent series resistance value by changing the thickness of the metal oxide film 14 in the final stage of the manufacturing processes, thereby making it possible to supply quickly ceramic capacitors having an equivalent series resistance value corresponding to the demand. COPYRIGHT: (C)1992,JPO&Japio

Theoretical studies of AC photothermal and AC electrothermal responses of semiconductor p-n junction devices

Abstract: Theoretical studies of the AC photothermal and AC electrothermal responses of semiconductor p-n junction devices with regard to photogenerated or applied voltages are presented, which cover the entire set of optical, electronic, thermal and geometric parameters involved in the operation of a conventional p-n junction device. In the theoretical analyses, the coupling between DC and AC components of the time-dependent transport equations of the minority carriers is considered, and the thermalization due to the minority carriers across the space-charge region and due to the equivalent series resistance effect are also taken into account.