SPICE Gummel-Poon Model Research Articles

Scalable large-signal model for SiGe HBTs

In this article, a scalable large-signal model for SiGe heterojunction bipolar transistors (HBTs) is presented. Compared with SPICE Gummel-Poon model, the proposed model has taken into account the self-heating effects, which is important for large-signal operations. The model includes a new base-collector breakdown description, which has taken the current dependence into account. This model allows exact modeling of all transistor parameters from single emitter size cells to other size devices. The scaling rules are shown in detail. The model is verified by the SiGe HBTs with emitter area of 0.3 × 20.3, 0.3 × 13.9, 0.3 × 9.9, and 0.3 × 1.9 um2. Excellent agreement has been achieved between modeled and measured data over a wide range of bias conditions and signal frequencies. The model has been implemented in Verilog-A using the ADS circuit simulator. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012. © 2012 Wiley Periodicals, Inc.

Generalized Early Voltage Model of Bipolar Transistors for Linearly Graded Germanium in Base

The standard Early voltage of the SPICE Gummel-Poon model (SGP) is generalized for SiGe npn heterojunction bipolar transistors (HBTs). An accurate model for Early effects compatible with the SGP model is obtained considering graded germanium induced bandgap narrowing effect in the base in modern SiGe HBTs and simplified to a compact model which is consistent with ISE TCAD simulation results. The presentation of the Early effect model is significant for the design and simulation of the high performance SiGe BiCMOS technology.

Electro-thermal stress effect on InGaP/GaAs heterojunction bipolar low-noise amplifier performance

Abstract This paper investigates the electro-thermal stress-induced performance degradation of a cascode low-noise amplifier built using advanced InGaP/GaAs heterojunction bipolar transistors. Changes in device characteristics due to the electro-thermal stress are examined experimentally. SPICE Gummel-Poon model parameters extracted from the pre- and post-stress HBT measurement data are then used in Cadence SpectreRF simulator to study the impact of the electro-thermal stress on the InGaP/GaAs LNA’s RF performance.

Silicon controlled rectifier (SCR) compact modeling based on VBIC and Gummel–Poon models

Silicon controlled rectifier (SCR) is frequently used for electrostatic discharge (ESD) protection applications. For computer-aided design purposes, a macromodel can be constructed for such a device, but a model for the NPN and PNP bipolar transistors imbedded in the SCR is required in the macromodel development. In the paper, we use both the Vertical Bipolar Inter-Company (VBIC) and SPICE Gummel–Poon (SGP) models for these bipolar transistors and compare the perspective macromodel results. Measurements obtained from the transmission line pulsing (TLP) tester are also included to assess the suitability and pros and cons of the VBIC and SGP models for the SCR ESD modeling.

A computationally efficient physics-based compact bipolar transistor model for circuit Design-part II: parameter extraction and experimental results

A compact bipolar transistor model was presented in Part I that combines the simplicity of the SPICE Gummel-Poon model (SGPM) with some major features of HICUM. The new model, called HICUM/L0, is more physics-based and accurate than the SGPM but at the same time, from a computational point of view, suitable for simulating large circuits. In Part II, a parameter determination procedure is described and demonstrated for a variety of SiGe process technologies.

A computationally efficient physics-based compact bipolar transistor model for circuit Design-part I: model formulation

A compact bipolar transistor model is presented that combines the simplicity of the SPICE Gummel-Poon model (SGPM) with some major features of HICUM. The new model, called HICUM/L0, is more physics-based and accurate than the SGPM and at the same time, from a computational point of view, suitable for simulating large circuits. The new model has been implemented in Verilog-A and, as compiled code, in various commercial circuit simulators. In Part I, the fundamental model formulation is presented along with a derivation of the most important equations. Experimental results are shown in Part II.

Advanced SPICE modelling of SiGe HBTs using VBIC model

The vertical bipolar intercompany (VBIC) model has been applied to silicon-germanium heterojunction bipolar transistors (SiGe HBTs). The model includes the improved Early effect, quasi-saturation, substrate parasitic, avalanche multiplication, and self-heating. Several device parameters have been extracted from SiGe HBTs and implemented in the VBIC model. A comparison is made with the SPICE Gummel-Poon model. The usefulness and accuracy of the VBIC model for SiGe HBTs are demonstrated by way of comparison of simulated and measured room temperature device data.

SiGe HBTs model converting technique from SGP to VBIC model

A new parameter extraction methodology — local ratio evaluation is presented which is well suitable for converting one model to another. An example is given for VBIC model extraction by going through SPICE Gummel–Poon (SGP) model. It is based on the fact that VBIC model is a direct enhancement and extension of SGP model. First, the standard SGP model is extracted in the standard way. Next, SGP model parameters are directly converted to those in VBIC model. Local modifications are subsequently carried out for those parameters that are affected by different equations used in the two models. Finally, new model parameters for enhanced modeling features are introduced by evaluating the difference between measurement and simulation.

Physics-based minority charge and transit time modeling for bipolar transistors

It has been well known for many years that the transit time model used in the SPICE Gummel-Poon model (SGPM) is not adequate for reliable design of circuits operating either at high current densities (including quasi-saturation), which is often the case in high-speed integrated circuits, or at low voltages, which is important for low-power applications. In addition, extraction of the SGPM's transit time model parameters is often very difficult and time consuming. Although various proposals for modeling the transit time were published in the past, most of them are not suited for compact transistor models required in circuit simulation from a numerical, parameter extraction and lateral scaling point of view. In this paper, a set of minority charge and transit time equations is derived which are physics-based and laterally scaleable as well as suitable for incorporation into compact models. Experimental results of the new model are presented in terms of transit time and transit frequency versus bias (I/sub C/, V/sub CE/), geometry, and temperature, showing excellent agreement for different types of silicon homojunction bipolar transistors.

A SPICE compatible subcircuit model for lateral bipolar transistors in a CMOS process

This paper describes a SPICE compatible subcircuit model of a lateral pnp transistor, which was fabricated in a 0.6 /spl mu/m CMOS process. The extraction of a dc parameter set for the lateral device is more complicated than for a vertical device because of the presence of two parasitic vertical bipolar transistors which are formed by the emitter/collector, the base and the substrate regions. The SPICE Gummel-Poon model does not predict the substrate current accurately. This paper proposes a method which involves the use of a subcircuit incorporating three SPICE Gummel-Poon models [representing one lateral and two parasitic vertical bipolar junction transistors (BJT's)]. The development of this model, its implementation and the results obtained are outlined and discussed. This circuit model is SPICE compatible and can thus be used in commercial simulators. The model provides good agreement over a wide range of measured dc data including substrate current prediction.

A scaleable, statistical SPICE Gummel-Poon model for SiGe HBTs

A scaleable, statistical model has been developed for silicon germanium heterojunction transistors (SiGe HBTs), which are components of a commercially available BiCMOS technology for high-frequency applications. The SPICE Gummel-Poon (SGP) model parameters are scaled, and statistics added, using language features built into HSPICE, DC and AC fit is good over a wide range in emitter sizes, allowing an open-ended set of devices to be used with valid modeling capabilities. Features of IBM's HBT technology that contribute to the scaleability of the technology are discussed.

VBIC95: an improved bipolar transistor model

A new compact bipolar transistor model for circuit simulators that has already received widespread support in the industry, is considered. The model, VBIC95, was constructed to be the industry standard replacement for the aging SPICE Gummel-Poon model (SGP). Users of the 20-year-old SGP model have found it to be inadequate in representing, many of the physical effects important in modern bipolar transistors used in analog and mixed-signal microcircuits. VBIC95 advantages include: 1. Improved static temperature modeling; 2. Correct implementation of the Early effect; 3. An improved forward-biased junction capacitance option; 4. Inclusion of overlap capacitance; 5. Null high-current modeling (updated with NPN V/sub sat/ equations); 6. Improved high-level diffusion capacitance modeling; 7. Inclusion of substrate transistor with R/sub c/ and variable Beta; 8. Approximate accounting for distributed effects in the input circuit; 9. Consistent treatment of excess phase in transient and small signal analyses; 10. Models weak avalanche effect; 11. All equations differentiable to a high order; 12. Distributed input impedance models AC emitter crowding; and 13. No special test structures required thus minimizing problems with extracting the new model parameters from old data.

VBIC95, the vertical bipolar inter-company model

This paper details the VBIC95 bipolar junction transistor (BJT) model. The model was developed as an industry standard replacement for the SPICE Gummel-Poon (SGP) model, to improve deficiencies of the SGP model that have become apparent over time because of the advances in BJT process technology. VBIC95 is still based on the Gummel-Poon formulation, and thus can degenerate to be similar to the familiar SGP model. However, it includes improved modeling of the Early effect, quasi-saturation, substrate and oxide parasitics, avalanche multiplication, and temperature behavior that can be invoked selectively based on model parameter values.

Physical modeling of lateral scaling in bipolar transistors

The dependence of important transistor characteristics, such as transit frequency, on emitter width and length is modeled on a physical basis. Closed-form explicit analytical equations are derived for modeling the emitter size dependence of the low-current minority charge and transit time, the critical current indicating the onset of high injection in the collector, and the stored minority charge in the collector at high injection. These equations are suited for application in various compact transistor models such as the SPICE Gummel-Poon model (SGPM) as well as the advanced models HICUM and MEXTRAM. As demonstrated by two- and three-dimensional device simulation and measurements, combination of the derived equations with HICUM results in accurate prediction of the characteristics of transistors with variable emitter length and width. As a consequence, the new model makes the conventional transistor library unnecessary and offers bipolar circuit designers the flexibility to use the transistor size that fits the application best.

MODELLA-a new physics-based compact model for lateral p-n-p transistors

A lateral p-n-p compact model, suitable for computer-aided circuit design purposes, is introduced. In this formulation, called MODELLA, the equivalent circuit topology, analytical equations, and model parameters are derived directly from the physics and structure of the lateral p-n-p. MODELLA incorporates current crowding effects, substrate effects, and a bias-dependent output conductance and it uses the approach to lateral p-n-p high injection modeling whereby the main currents and charges are independently related to bias-dependent minority-carrier concentrations. Model-specific aspects of the parameter determination strategy are discussed; the Ning-Tang resistance determination method, for example, is shown to be highly suitable for lateral p-n-p devices. The effectiveness of this strategy and the improved performance of this physics-based formulation become evident in comparisons between MODELLA and the standard SPICE Gummel-Poon model using measured device characteristics. >