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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]

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 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]

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]

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.

Abstract: An analytical model of electrostatics and drain current for quadruple-gate MOSFET operating in the subthreshold regime is presented. The model is based on conformal mapping techniques and it captures the 3D electrostatics in the device body. We basically solve the electrostatics for practically undoped body, and thus both depletion charges and free charge carriers are neglected, thus allowing us to solve the Laplace equation in the subthreshold regime. We extend 2D conformal mapping techniques to the 3D device using appropriate scaling lengths. The obtained model has been verified by 3D numerical simulations from the ATLAS device simulator by Silvaco. [Copyright &y& Elsevier]

Abstract: We present 2-D physics based modeling of short-channel double-gate MOSFETs of nanoscale dimensions. We have derived a precise, self-consistent framework model for the device electrostatics, the drain current, and the charge conserving capacitances, covering all regimes of device operation from subthreshold to strong inversion. The modeling has no adjustable parameters and implicitly incorporates scaling with device dimensions and material composition. The foundation of the 2-D modeling is an analytical description of the inter-electrode capacitive coupling between the four electrodes, based on conformal mapping techniques. The model is shown to be in excellent agreement with numerical simulations. [Copyright &y& Elsevier]

An analytical model for the anomalous behavior of the halo or pocket implanted MOSFETs is presented for both strong and weak inversion operation. Even though most of the drain current reduction due to the pocket implantation can be explained by the effective threshold voltage of halo MOSFETs, a further decrease has been observed that can be attributed to the effects of the halo implants on the effective mobility as well as threshold voltage of these devices. Taking into account the effect of the regionally distinctive distributions of the physical quantities related to the charge transport, a simple drain current model suitable for implementation in circuit simulators is developed. The presented analytical model is shown to agree well with 2D simulations and experiments. The reduced dependency of the subthreshold current on the gate length is also explained. [Copyright &y& Elsevier]