Ebers-Moll Model Research Articles

PSPICE modelling of self-heating effects on lateral bipolar magneto-transistors

In this paper, PSPICE modelling of self-heating effects on the time response of electronic processing lateral bipolar magneto-transistor (LMT) circuits are covered. The self-heating effects in the relatively high base resistors of the LMTs, in the transistors itself (using a simplified Ebers–Moll model) and also in the thermal capacitance of the epoxy based encapsulation are considered. It has been found from the simulations and the experiment that the effective time constant of the output voltage increases with internal power dissipation and that there also appears dynamic hysteresis of the response to a magnetic field. It is concluded that LMTs should be as matched as possible and that especially developed packages are required to minimise these deleterious effects.

Temperature dependence and electrical properties of dominant low-frequency noise source in SiGe HBT

The temperature dependence and electrical properties of the dominant low-frequency noise source in a SiGe HBT have been investigated. By employing a temperature variation of the device to get a variation of the base or collector current independently of each other, it is shown that the dominant noise source is strongly dependent on the collector current, but only weakly dependent on the base current. A modified Ebers-Moll model is presented that accounts for the collector current dependence of the dominant noise source and simultaneously accounts for the temperature dependence of /spl beta/. Using the modified Ebers-Moll model, the understanding of the physical positioning of the noise source is simplified.

Modelling of multilayer thin-film solar cells

A new multilayer solar cell has recently been introduced. This cell requires only top and bottom electrical contact. Internal feedback paths within this multilayer cell ensure the addition of partial photogenerated currents collected at individual pn junctions. An extended Ebers–Moll model was developed, which turned out to be a convenient tool for an examination of the physical parameters of the cell and for the optimisation of its internal structure. The current–voltage characteristics of floating junction solar cells are calculated and a comparison with other multilayer solar cell structures presented. Copyright © 1999 John Wiley & Sons, Ltd.

Study of In0.49Ga0.51P/GaAs/In0.49Ga0.51P doubleδ-doped heterojunction bipolar transistor

A lattice-matched In0.49Ga0.51P/GaAs/In0.49Ga0.51P doubleδ -doped heterojunction bipolar transistor, prepared by low-pressure metal organic chemical vapor deposition (LP-MOCVD), is fabricated successfully and reported. Due to the insertion of δ -doped sheets and setback layers both at base–emitter (B–E) and base–collector (B–C) heterojunctions, the potential spikes are suppressed significantly. In addition, the electron blocking effect is removed and a dramatic improvement of current gain is obtained. A modified Ebers–Moll model is employed to study and analyse the device performances. The experimental results show that the common-emitter current gain over 210 at the collector current of 35 mA and an offset voltageΔVCE smaller than 50 mV are obtained. Also, a lower knee-shaped voltage of 1.4 V at the collector current of 40 mA is observed. These results indicate that the device studied is a good candidate for high-speed and high-power circuit applications.

Large-signal characterization of AlGaAs/GaAs HBT's

A modified Ebers-Moll model is developed for AlGaAs/GaAs heterojunction bipolar transistors (HBT's). The self-heating effect is modeled by a thermal-electrical sub-circuit. The model is verified by comparing the large-signal RF simulation and measurement. Good agreement is achieved when the HBT is biased at low DC power dissipation. The discrepancy between simulation and measurement when the HBT is biased at high DC power dissipation is explained by considering the self-heating effect under large-signal RF excitation.

Technological compensation circuit for accurate temperature sensor

A compensation circuit has been developed to reduce the V BE wafer spread of a bipolar transistor by taking advantage of the correlation between pinched base resistor R P and I S of the Ebers-Moll model. This compensation circuit was used in the design of a Celsius temperature sensor with intrinsic reference, improving its accuracy at least five times within the 0 °C to 100 °C interval. Accuracy has been calculated considering wafer level statistical modeling of bipolar IC parameters, circuit sensitivity, and worst case circuit simulation. This technological compensation procedure allows to obtain an accurate IC temperature sensor without final trimming at wafer level.

DC characterisation of HBTs using the observed kink effect on the base current

Large parasitic series resistances of the heterostructure bipolar transistors are shown to cause a sharp rise in the base current of the Gummel plot at high current levels. This effect is analysed and attributed to a forward-biased base–collector junction due to the large voltage drop across the collector series resistance of the device. The occurrence of this effect results in a severe reduction in current gain of the device at high current levels. A DC Ebers–Moll model is presented with all the parameters extracted from DC characterisation of the HBT, and an excellent fit between the model and experimental data is obtained. The method can be used to determine the base, collector and emitter series resistances of the bipolar transistors for DC applications. Finally, the effect of temperature on the onset of this effect is demonstrated.

Harmonic and two-tone intermodulation distortion analyses of the inverted InGa/InAlAs/InP HBT

Harmonic and two-tone intermodulation distortion analyses of the InGaAs/InAlAs/InP collector-up heterojunction bipolar transistor (HBT) are performed by a simple Ebers-Moll model. The parasitic elements of the equivalent circuit are extracted at zero bias by numerical optimization. A semianalytical approach is used to extract the intrinsic parameters of the small-signal equivalent circuit at nonzero bias points. Appropriate equations given by device physics are fitted to the bias variation of intrinsic parameters so that the Ebers-Moll model parameters can be extracted. Agreement between simulation and measurement of harmonic and intermodulation distortion is achieved.

DC modeling and characterization of AlGaAs/GaAs heterojunction bipolar transistors for high-temperature applications

The large signal dc characteristics of AlGaAs/GaAs heterojunction bipolar transistors (HBT) at high temperatures (27/spl deg/-300/spl deg/C) are reported. A high-temperature SPICE model is developed which includes the recombination-generation current components and avalanche multiplication which become extremely important at high temperatures. The effect of avalanche breakdown is also included to model the current due to thermal generation of electron/hole pairs causing breakdown at high temperatures. A parameter extraction program is developed and used to extract the model parameters of HBT's at different temperatures. Fitting functions for the model parameters as a function of temperature are developed. These parameters are then used in the SPICE Ebers-Moll model for the dc characterization of the HBT at any temperature between (27/spl deg/-300/spl deg/C). >

Large-signal numerical and analytical HBT models

Several large-signal heterojunction bipolar transistor (HBT) models are investigated to determine their usefulness at millimeter-wave frequencies. The most detailed model involves numerically solving moments of the Boltzmann transport equation. A description of the numerical model is given along with several simulated results. The numerical model is then used to evaluate two analytical HBT models, the conventional Gummel-Poon model and a modified Ebers-Moll model. It is found that the commonly used Gummel-Poon model exhibits poor agreement with numerical and experimental data at millimeter-wave frequencies due to neglect of transit-time delays. Improved agreement between measured and modeled data results b including transit-time effects in an Ebers-Moll model. The simple model has direct application to millimeter-wave power amplifier and oscillator design. Several measured results are presented to help verify the simple model.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Operational state analysis using piecewise-linear diode model with a switch and its evaluation

One of the methods for analysis of the operational state of the transistor network is the method based on the piecewise-linear diode model. When the bipolar transistor network is analyzed using the Ebers-Moll model containing the diode model composed of the voltage source and the switch, it may happen that a cut-set composed only of current sources or a loop composed only of voltage sources is formed in the course of iteration. Also, depending on the state of the switch, it may happen that a subnetwork is separated. In such cases, the coefficient matrix of the network equation becomes singular. From such a viewpoint, this paper discusses the method in which the modified nodal equation is constructed using the piecewise-linear diode model containing a switch, and a high-speed analysis is executed while avoiding the singularity problem by simultaneously changing the states of more than one switch. In the piecewise-linear diode model, the reverse-biased characteristic is approximated by connecting a linear resistor R in parallel to the switch branch so that the electrical characteristic of the diode is not violated. The forward-biased characteristic is approximated by inserting a linear resistor r in series to the switch branch. It is verified that by using the piecewise-linear diode model containing a switch, the singularity problem is avoided and the limit cycle problem is greatly ameliorated.

On the harmonic distortion coefficients of active-loaded amplifiers

Starting from the modified Ebers-Moll model which represents the Early effect more accurately than conventional models with the Early voltage, new expressions to calculate the harmonic distortion coefficients of active-loaded BJT amplifiers are derived and applied to the determination of the optimum operating point, where the total harmonic distortion is at a minimum. The results are not obtainable with SPICE, therefore derived expressions provide the possibility of completing the simulation with manual calculations.

マトリクス平面ディスプレイの素子選択における３状態スイッチング

This paper describes an analog 3-state switching circuit which supplies current to display elements to set the display or undisplay state of the matrix display panel. The circuit consists of two groups of complementary transistors, and supplies either positive current, negative current or isolation by three control voltages. When applied to the matrix circuit, elements can be collectively selected in the row or the column.Experimental results are verified through results of circuit analysis using Ebers-Moll's model. The source voltage and the control voltage are determined by considering the maximum load current. The 3-state circuit design and the matrix display circuit design with 3-state circuits are simple and power is not consumed during the display or the undisplay state.

The DC characteristics of GaAs/AlGaAs heterojunction bipolar transistors with application to device modeling

A complete DC model for the heterojunction bipolar transistor (HBT) is presented. The DC characteristics of the HBT are compared with the Ebers-Moll (EM) model used by conventional bipolar junction transistors (BJTs) and implemented in simulation and modeling programs. It is shown that although the details of HBT operation can differ markedly from those of a BJT, a model and a parameter extraction technique can be developed which have physical meaning and are exactly compatible with the EM models widely used for BJTs. Device I-V measurements at 77 and 300 K are used to analyze the HBT physical device performance in the context of an EM model. A technique is developed to extract the device base, emitter, and collector series resistances directly from the measured I-V data without requiring an ideal exp(qV/sub be//kT) base current as reference. Accuracies of the extracted series resistances are assessed. AC parameters of HBT are calculated numerically from the physical device structure. For modeling purposes, these parameters are shown to be comparable with those of conventional BJTs. >

Three-junction device simulation model

A numerical model of a three-junction device (pnpn family) is presented. It particularly allows the simulation of the external characteristics of the gate turn-off thyristor (GTO) which is used in electronic power convertors. The model is an extension of the Ebers-Moll model and it is implemented (built) in the SPICE circuit simulator code.

Numerical method for analyzing transient and steady states of sine wave oscillator circuit with stiffness

AbstractThis paper proposes a method for analyzing the transient and steady states of a sine wave oscillator circuit with reactive elements which have large differences in their values. These reactive elements can be divided broadly into three categories: elements for determining the frequency of the oscillation; very small elements such as stray capacitors in the transistor; and very large elements such as by‐pass capacitors. The circuit equation is represented by an autonomous nonlinear differential equation with the values of these elements. There are remarkable differences in magnitude between the eigenvalues of the linear parts of the equation. In this paper, first, we describe the method for solving numerically the differential equation regardless of the stiffness by the asymptotic method developed by Krylov, Bogolyubov and Mitropolskiy. Second, we present the method for obtaining solutions of the differential equation with regard to the stiffness by combining the asymptotic method with numerical integration. Especially, when we obtain the transient solution, we demonstrate that the application of the interpolation method to the asymptotic method reduces the computing time considerably. As examples, we consider the CR sine wave oscillator circuit using the Ebers–Moll model of transistors.

An Ebers-Moll model for the heterostructure bipolar transistor

An Ebers-Moll model for the heterostructure bipolar transistor (HBT) is developed. The model describes both single and double heterojunction transistors with or without band spikes and applies to uniform or graded base HBTs. Model parameters are directly related to device parameters such as doping densities, dimensions and band spikes. Junction velocities are introduced to describe the transport of carriers across the junctions. Results demonstrate that even for compositionally graded junctions, transport across the junctions may limit HBT performance if the base is graded. Use of the model is illustrated by examining a recently proposed technique for extracting conduction band spikes by comparing forward and inverted I- V characteristics.

Application of modified Ebers-Moll model to nonlinear distortion analysis of transistor amplifiers

Application of the modified Ebers-Moll model to low-frequency nonlinear harmonic distortion analysis of transistor amplifiers is discussed. The calculated values for two types of transistor amplifiers are compared with measured values and are found to be in good agreement. Therefore the model can be used in design of low-distortion audio amplifiers.

Modified ebers-moll model

A new modified Ebers-Moll model is described. The model represents a bipolar transistor accurately in the active operating region at low frequencies. It is therefore suitable for computer-aided nonlinear distortion analysis of transistor amplifiers.

An Improved Bipolar Junction Transistor Model for Electrical and Radiation Effects

The use of bipolar technology in hardened electronic design requires an in-depth understanding of how the Bipolar Junction Transistor (BJT) behaves under normal electrical and radiation environments. Significant improvements in BJT process technology have been reported, and the successful use of sophisticated Computer Aided Design (CAD) tools has aided implementation with respect to specific families of hardened devices. The most advanced BJT model used to date is the Improved Gummel-Poon (IGP) model which is used in CAA programs such as the SPICE II and SLICE programs. The earlier Ebers-Moll model (ref 1 and 2) has also been updated to compare with the older Gummel-Poon model. This paper describes an adaptation of an existing computer model which incorporates the best features of both models into a new, more accurate model called the Improved Bipolar Junction Transistor model. This paper also describes a unique approach to data reduction for the B(Ic) and VBE (ACT) vs Ic characterizations which has been successfully programmed in Basic using a Commodore PET computer. This model is described in the following sections.