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We present the latest developments in Advance SPICE Model for GaN (ASM GaN) HEMTs in this paper. The ASM GaN model has been recently selected as an industry-standard compact model for GaN radio frequency (RF) and power devices. The core surface-potential calculation and the modeling of real device effects in this model are presented. We discuss the details of the nonlinear access region model and enhancement in this model to include a physical dependence on barrier thickness. We also present the novel model feature of configurable field-plate modeling and discuss the extraction procedure for the same. New results with the ASM GaN model on high-frequency and enhancement-mode GaN power devices are also presented. [ABSTRACT FROM AUTHOR]

Focuses on a study that developed an analytical formulation for carrier transport in the two-dimensional conducting channel of the aluminum gallium arsenide/gallium arsenide high electron mobility transistor (HEMT). Properties of the relaxation time approximation; Basic equations for the HEMT; Model calculations.

Reports on the derivation of expressions for electron scattering rates in mercury cadmium telluride accounting for correct wave functions in narrow-band-gap materials. Material parameters used in the calculation; Information on the scattering rates; Discussion on the Monte Carlo simulation.

We present an analytical modeling framework to describe the effects of surface donor states on the properties of bare lattice-matched InAlN/AlN/GaN heterostructures. The distributed surface states are characterized by a donor density and a donor level that relate directly to the observable 2-D electron density and surface barrier height of the device. This allows the model parameters to be extracted from experimental data, enabling the model to be used for the characterization and the predictive design of advanced high-power, high-frequency devices. [ABSTRACT FROM AUTHOR]

In this paper, we present a physics based analytical model to describe the effect of SiN passivation on two-dimensional electron gas density and surface barrier height in AlGaN/GaN heterostructures. The model is based on an extraction technique to calculate surface donor density and surface donor level at the SiN/AlGaN interface. The model is in good agreement with the experimental results and promises to become a useful tool in advanced design and characterization of GaN based heterostructures. [ABSTRACT FROM AUTHOR]

In this paper, a physics based analytical model is presented for calculation of the two-dimensional electron gas density and the bare surface barrier height of AlGaN/AlN/GaN material stacks. The presented model is based on the concept of distributed surface donor states and the self-consistent solution of Poisson equation at the different material interfaces. The model shows good agreement with the reported experimental data and can be used for the design and characterization of advanced GaN devices for power and radio frequency applications. [ABSTRACT FROM AUTHOR]

This paper presents physics-based compact models for the C-V and I-V characteristics of AlGaN/GaN HEMT devices. The contribution of only the first energy level in the triangular quantum well at the AlGaN/GaN interface (where most of the charge carriers of the 2-DEG channel reside) is considered, which resulted in an accurate and simple unified charge control model. Based on this, analytical models of the drain current, the gate charge, and the gate capacitances have been developed. The models cover all the different operating regimes of a device. The excellent agreements between the model and measured C-V and I-V characteristics of devices with different gate lengths have demonstrated the validity of the model. [ABSTRACT FROM PUBLISHER]

Various physics based modeling schemes for multigate MOSFETs are presented. In all cases, the models are derived from an analysis of the device body electrostatics in terms of two- or three-dimensional Laplace's and Poisson's equations, where short-channel and scaling effects are implicitly accounted for. Thus a comprehensive modeling framework is derived for the subthreshold electrostatics of double-gate MOSFETs based on a conformal mapping analysis of the potential distribution in the device body arising from the inter-electrode capacitive coupling. This technique is also applied to the circular gate-all-around MOSFET by utilizing the symmetry properties of this device. For both these devices, the modeling is extended to include the strong inversion regime by a self-consistent procedure that simultaneously allows the calculation of the quasi-Fermi potential distribution, the drain current, and the intrinsic capacitances. In an alternative modeling framework, covering a wide range of multigate devices in a unified manner, the potential distribution is derived from a select set of isomorphic trial functions that reflect the geometry and symmetry properties of the devices. Modeling parameters used are self-consistently determined by imposing boundary conditions associated with Laplace's or Poisson's equation. Finally, the effects of quantum mechanical confinement are discussed for ultra thin body devices. The results of the modeling are in excellent agreement with numerical simulations. [ABSTRACT FROM AUTHOR]

We present an accurate and robust surface-potential-based compact model for simulation of circuits designed with GaN-based high-electron mobility transistors (GaN HEMTs). An accurate analytical surface-potential calculation, which we developed, is used to develop the drain and gate current model. The model is in excellent agreement with experimental data for both drain and gate current in all regions of device operation. We show the correct physical behavior and mathematical robustness of the model by performing various benchmark tests, such as DC and AC symmetry tests, reciprocity test, and harmonic balance simulations test. To the best of our knowledge, this is the first time a GaN HEMT compact model passing a range of benchmark tests has been presented. [ABSTRACT FROM AUTHOR]

In this paper, we present a physics-based model for accurate simulation of intermodulation distortion (IMD) in GaAs pseudomorphic HEMTs at 2 GHz. We combine the surface-potential-based drain-current model previously developed by us with the standard topology used in these devices for accurate nonlinear simulations. The proposed model is in excellent agreement with measured IMD data at multiple dc bias points varying from close-to cutoff voltage to the high-conduction region. We also analyze the impact of various model elements and physical effects on IMD behavior of the device. Furthermore, the popular Volterra series coefficients for the drain current nonlinearity are analyzed and their relative importance with respect to the overall device nonlinearity is assessed. [ABSTRACT FROM PUBLISHER]

In this paper, we present a modeling and simulation methodology for safe-operating-area (SOA)-aware circuit design in dc and pulsed-mode operation of high-voltage MOSFETs (HV MOSFETs). The developed methodology gives an accurate description of the SOA of devices under dc and, more importantly, transient inputs, taking into account the width and duty-cycle of the pulse. To the best of the authors' knowledge, this is the first time such a methodology integrated with circuit design tools is presented. It is shown through simulation of standard circuits of HV MOSFETs that the proposed methodology avoids overdesigns and enables circuit designers to use the high-voltage technology to its full potential. [ABSTRACT FROM PUBLISHER]

A surface potential (SP)-based analytical model for intrinsic charges in AlGaN/GaN high electron mobility transistor devices is presented. We have developed a precise analytical method to calculate the Fermi-level position Ef from a consistent solution of Schrodinger's and Poisson's equations in the quantum well, considering the two important energy levels. The accuracy of our Ef calculation is on the order of femto-volts for the full range of bias voltage. The SP calculated from Ef is used to derive an analytical model for intrinsic charges in these devices. The model is in excellent agreement with experimental data. [ABSTRACT FROM PUBLISHER]

We have presented an RF MEMS tuneable lowpass filter. Both distributed transmission lines and RF MEMS capacitances were used to replace the lumped elements. The use of RF MEMS capacitances gives the flexibility of tuning the cutoff frequency of the lowpass filter. We have designed a low-pass filter at 9-12GHz cutoff frequency using the theory of stepped impedance transmission lines. A prototype of the filter has been fabricated using parallel plate capacitances. The variable shunt capacitances are formed by a combination of a number of parallel plate RF MEMS capacitances. The cutoff frequency is tuned from C to X band by actuating different combinations of parallel capacitive bridges. The measurement results agree well with the simulation result. [ABSTRACT FROM AUTHOR]

In this brief, we present a physics-based analytical model for 2-D electron gas density ns in AlGaN/GaN high-electron mobility transistors. The proposed model accounts for the interdependence between Fermi level Ef and ns. The model is developed by considering the variation of Ef, the first subband E0, the second subband E1, and ns with applied gate voltage Vg. The proposed model is in very good agreement with numerical calculations. [ABSTRACT FROM AUTHOR]

A physics-based compact subthreshold current model for short-channel nanoscale double-gate MOSFETs is presented. The potential is modeled using conformal mapping techniques in combination with parabolic approximations. For subthreshold conditions, we have assumed that the electrostatics is dominated by capacitive coupling between the body electrodes. Hence, the potential is obtained as an analytical solution of the 2-D Laplace equation. The current modeling is based on drift-diffusion theory. The modeling results are in good agreement with those of numerical simulations without the use of adjustable parameters. [ABSTRACT FROM AUTHOR]

A precise modeling framework for short-channel nanoscale double-gate (DG) and gate-all-around (GAA) MOSFETs is presented. For the DG MOSFET, the modeling is based on a conformal mapping analysis of the potential distribution in the device body arising from the interelectrode capacitive coupling, combined with a self-consistent procedure to include the effects of the inversion charge. The DG interelectrode coupling, which dominates the subthreshold behavior of the device, can also be applied with a high degree of precision to the cylindrical GAA MOSFET by performing a simple geometric scaling transformation to account for the difference in gate control in the two devices. Near threshold, self-consistent procedures invoking Poisson's equation in combination with boundary conditions and suitable modeling expressions for the potential are applied to the two devices. In strong inversion, these solutions converge to those of the respective long-channel devices. The drain current is calculated as part of the self-consistent treatment. The results for both the electrostatics and the current are in excellent agreement with numerical simulations. [ABSTRACT FROM AUTHOR]

This paper aims to explore ways of securely operating electrical instruments via the Internet. A system is presented, which allows a person connected to a local area network (LAN) to operate multiple electrical instruments located at other LANs via a public web server on the Internet, regardless of firewalls, proxy servers, or source network address translators that separate them. A full system test has been performed, and data from the test are later presented. The solution is based on Microsoft .NET Remoting, which is part of the Microsoft .NET Framework. A viable application is Internet-enabled calibration, and possible users are national measurement institutes and calibration laboratories. The solution is general and does not depend on the underlying network connections involved as long as hypertext transfer protocol over secure sockets layer is supported. [ABSTRACT FROM AUTHOR]

Compact-modeling principles and solutions for nanoscale double-gate and gate-all-around MOSFETs are explained. The main challenges of compact modeling for these devices are addressed, and different approaches for describing the electrostatics, the transport mechanisms, and the high-frequency behavior are explained. Several approximations used to derive analytical solutions of Poisson's equation for doped and undoped devices are discussed, and the need for self-consistency with Schrödinger's equation and with the current continuity equation resulting from the transport models is addressed. Several techniques to extend the compact modeling to the high-frequency regime and to study the RF performance, including noise, are presented and discussed. [ABSTRACT FROM AUTHOR]

We have developed a 2D model for double-gate SOI MOSFET based on a solution of the Laplacian for the device body utilizing conformal mapping techniques. The model yields explicit expressions for the subthreshold and near-threshold electrostatics of the device, including the perpendicular electrical field and the potential distributions along the silicon/insulator interfaces and at the center gate-to-gate axis. From these expressions, we derive information on the threshold conditions, the potential barrier topography, and the electron density distribution in the device under different biasing conditions. This model constitutes a framework for very precise, scalable, compact models of nanoscale MOSFETs. [ABSTRACT FROM AUTHOR]

For the purpose of simulating the effects of neutron radiation damage on bipolar circuit performance, we have developed a bipolar junction transistor SPICE model that incorporates displacement damage effects. A physics-based formalism is used for describing the radiation effects within the framework of the Gummel-Poon model. A model structure that includes the dependence of neutron fluence on the relevant SPICE parameters is outlined, from which a simplifed radiation model is established. The latter is presented and implemented in AIM-Spice, and it is shown to agree quite well with experiments. Dynamic effects including annealing are also discussed. [ABSTRACT FROM AUTHOR]

Focuses on a study which examined a dynamic model for photoelectric effect in bipolar devices exposed to a wide range of ionizing radiation intensities. Description of the device model; Results of the diode simulations; Details on the MEDICI simulations; Conclusion.

Provides information on a study which described a physics based, analytical direct current model accounting for short channel effects for hydrogenated amorphous silicon thin film transistors (TFT). How the devices were grouped in the experiments; Dependence of TFT characteristics on ambient temperature; Self-heating effects; Kink effect; Scaling effects; Conclusion.

Deals with a study which described an enhanced model for deep submicron heterostructure field effect transistors suitable for implementation in computer aided design software packages. Discussion on the equivalent circuit and the direct current model; Verification of the model in a circuit environment; Conclusion.

We review recent physics-based, analytical DC models for amorphous silicon (a-Si), polysilicon (poly-Si), and organic thin film transistors (TFTs), developed for the design of novel ultra high-resolution, large area displays using advanced short-channel TFTs. In particular, we emphasize the modeling issues related to the main short-channel effects, such as self-heating (a-Si TFTs) and kink effect (a-Si and poly-Si TFTs), which are present in modern TFTs. The models have been proved to accurately reproduce the DC characteristics of a-Si:H with gate lengths down to 4 μm and poly-Si TFTs with gate lengths down to 2 μm. Because the scalability of the models and the use of continuous expressions for describing the characteristics in all operating regimes, the models are suitable for implementation in circuit simulators such as SPICE. [ABSTRACT FROM AUTHOR]

We present a review of modern analog simulation techniques based on time- and frequency-domain algorithms. For time-domain techniques, important topics such as circuit decomposition, relaxation methods, latency, multirate integration, continuation methods, parallel algorithms, and finite difference time-domain methods are discussed. Frequency-domain simulation techniques included are harmonic balance, harmonic relaxation, harmonic-Newton, spectral balance, methods for quasiperiodic circuits, and device modeling for frequency domain simulators. Also included are examples of modern simulators. [ABSTRACT FROM AUTHOR]

We review recent advances in the modeling of novel and advanced semiconductor devices, including state-of-the-art MESFET and HFETs, heterodimensional FETs, resonant tunneling devices, and wide-bandgap semiconductor transistors. We emphasize analytical, physics-based modeling incorporating the important effects present in modern day devices, including deep sub-micrometer devices. Such an approach is needed in order to accurately describe and predict both stationary and dynamic device behavior and to make the models suitable for implementation in advanced computer aided design tool including circuit simulators such as SPICE. [ABSTRACT FROM AUTHOR]

We review the simulation and modeling techniques used for popular compound semiconductor devices such as the Heterostructure Field Effect Transistor (HFET), the Metal Semiconductor Field Effect Transistor (MESFET), and the Heterostructure Bipolar Transistor (HBT). Starting with the basic transport theory and the numerical simulation techniques based on this theory, we proceed to give examples of Monte Carlo simulations and of 2D balance equation simulations for investigating fundamental device properties and for exploring new design concepts. Next, we present analytical HFET and MESFET models suitable for circuit simulations. These models are based on the so-called universal FET modeling concept, and accurately reproduce FET I-V and C-V characteristics. Finally, we review basic simulation and modeling issues for HBTs. [ABSTRACT FROM AUTHOR]

Presents an analytical charge conserving capacitance model for intrinsic Gallium-Arsenide (GaAs) metal semiconductor field effect transistors (MESFET's). Illustration on the channel region of MESFET; Consideration of a typical MESFET structure with active layer thickness; Conclusion.

Presents a physically based analytical model for fully depleted silicon-on-insulator (SOI) metal oxide semiconductor field-effect transistors (MOSFET) Inclusion of the self-heating effect (SHE); Suitability of the model for use in circuit simulators; Other actors taken into account by the model.

We have experimentally investigated the threshold voltage shift due to negative bias temperature instability (NBTI). The NBTI stress in the absence of self-heating (SH) is performed at two different temperatures, i.e., T = \25\ ^\circ\C and \125\ ^\circ\C, at bias conditions: gate voltage Vgs = -\2\ \V and drain voltage Vds = \0\ \V. To evaluate the effect of NBTI in the presence of SH, the stress is performed at room temperature and at Vgs = -\2\ \V\ \and\ Vds = -\1\ \V. It has been observed that NBTI in the presence of SH causes a significant shift in the threshold voltage. [ABSTRACT FROM PUBLISHER]

A physics based analytical model is presented to describe the bare surface barrier height and the two-dimensional electron gas density in AlGaN/GaN heterostructures versus barrier layer thickness and Al content. Details of the model rely on the extraction of the critical thickness for strain relaxation based on the identification of a signature cusp in experimentally obtained bare surface barrier heights. This information is used to obtain the residual strain and total effective polarization when strain relaxation takes place. The model, which covers both unrelaxed and relaxed barriers, shows good agreement with reported experimental results and promises to become a useful tool in advanced design and characterization of GaN based heterostructures. [ABSTRACT FROM AUTHOR]

In this letter, we present an experimental evaluation of self-heating (SH) effects (SHEs) using S-parameter measurements for both n- and p-type SOI FinFETs. It is revealed that NFETs show a stronger SHE than PFETs, which ultimately leads to a higher variation of the intrinsic gain in NFETs. Our results also show that long-channel devices typically used in analog design show pronounced negative output conductance, which consequently leads to a negative intrinsic gain at low frequencies. Another implication of the strong SHE is that the interdie variability of the isothermal intrinsic gain gets “amplified” at lower frequencies due to SH. [ABSTRACT FROM PUBLISHER]

In this paper, a physics based analytical model for the bare surface barrier height and two dimensional electron gas density in AlGaN/GaN heterostructures is presented. The model is based on simple charge neutrality electrostatics across the AlGaN barrier layer and that a low density of surface donor states is the source of the two dimensional electron gas. The model shows good agreement with reported experimental results. [ABSTRACT FROM AUTHOR]