New Explicit Charge and Capacitance Models for Undoped Surrounding Gate MOSFETs (original) (raw)
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Explicit Analytical Charge and Capacitance Models of Undoped Double-Gate MOSFETs
IEEE Transactions on Electron Devices, 2007
An analytical, explicit, and continuous-charge model for undoped symmetrical double-gate (DG) MOSFETs is presented. This charge model allows obtaining analytical expressions of all total capacitances. The model is based on a unified-chargecontrol model derived from Poisson's equation and is valid from below to well above threshold, showing a smooth transition between the different regimes. The drain current, charge, and capacitances are written as continuous explicit functions of the applied bias. We obtained very good agreement between the calculated capacitance characteristics and 2-D numerical device simulations, for different silicon film thicknesses. Index Terms-Compact device modeling, Double-gate (DG) MOSFET, intrinsic capacitances.
Explicit continuous model for long-channel undoped surrounding gate MOSFETs
IEEE Transactions on Electron Devices, 2005
We present an analytical and continuous dc model for cylindrical undoped surrounding-gate (SGT) MOSFETs in which the channel current is written as an explicit function of the applied voltages. The model is based on a new unified charge control model developed for this device. The explicit model shows good agreement with the numerical exact solution obtained from the new charge control model, which was previously validated by comparison with three-dimensional numerical simulations. Index Terms-Charge control model, compact device modeling, surrounding-gate (SGT) MOSFETs. Benjamin Iñíguez (M'96-SM'03) received the B.S., M.S., and the Ph.D. degrees in physics from the University of the Balearic Islands, Spain, in 1989Spain, in , 1992Spain, in , and 1996. His doctoral research focused on the development of CAD models for short-channel bulk-Si and SOI MOSFETs.
An explicit analytical charge-based model of undoped independent double gate MOSFET
Solid-state Electronics, 2006
This paper describes an explicit analytical charge-based model of an undoped independent double gate (DG) MOSFET. This model is based on Poisson equation resolution and field continuity equations. Without any fitting parameter or charge sheet approximation, it provides explicit analytical expressions of both inversion charge and drain current considering long undoped transistor. Consequently, this is a fully analytical and predictive model allowing describing planar DG MOSFET as well as FinFET structures. The validity of this model is demonstrated by comparison with Atlas simulations.
Solid-State Electronics, 2009
This paper presents a charge-based compact model for predicting the current-voltage and capacitancevoltage characteristics of heavily doped long-channel cylindrical surrounding-gate (SRG) MOSFETs. Starting from Poisson's equation with fixed charge and inversion charge terms, a closed-form equation of inversion charge is obtained with the full-depletion approximation. Substituting this inversion charge expression into Pao-Sah's dual integral, a drain current expression with concise form is derived. Based on the Ward-Dutton linear-charge-partition method and the current continuity principle, all trans-capacitances are obtained analytically. The developed model is valid in all operation regions from the subthreshold to strong inversion and from the linear to the saturation region without any smooth function. The model predictions have been extensively compared with 3D numerical simulations and a good agreement is observed in most of the operation regions with a wide range of geometrical parameters.
Microelectronics Journal, 2016
The scaling of the solid-state devices are reaching its limit and it enhances the significant short channel effects. To overcome these problems, the surrounding-gate MOSFET is emerging as a promising structure and is a replacement of traditional MOSFETs. In this research work, authors have analyzed the performance of various parameters for the cylindrical surrounding-gate MOSFET using surface potential based approach and further transformation of variable technique to find the solution of the same differential equation. However, the modeling of terminal charge and trans-capacitance are also presented which is used for the circuit simulation. The influence of Gaussian doping (in vertical direction across the radius of the device) has been analyzed and solution of the surface-potential is derived based on the taylor series expansion.
International Journal of Circuits, Systems and Signal Processing, 2021
In this paper, we propose an analytical drain-current model for long-channel junctionless (JL) cylindrical surrounding-gate MOSFET (SRG MOSFET). It is based on surface-potential solutions obtained from Poisson’s equation using some approximations and separate conditions. Furthermore, analytical compact expressions of the drain-current have been derived for deep depletion, partial depletion, and accumulation mode. The confrontation of the model with TCAD simulation results, performed with Silvaco Software, proves the validity and the accuracy of the developed model
Unified quasi-static MOSFET capacitance model
IEEE Transactions on Electron Devices, 1993
An accurate calculation of MOSFET capacitancevoltage (C-V) characteristics has to account for the bulk charge which is affected by nonuniform doping profiles and shortchannel effects. In our approach based on the Unified Charge Control Model (UCCM), we relate the voltage dependencies of the bulk charge to the standard parameters of the body plots which are routinely measured during MOSFET characterization. The results of the C-V calculations based on this model are in good agreement with our experimental data and with the calculations based on the standard BSIM model. Compared to the BSIM simulations, our model more accurately describes capacitances related to the bulk charge and the device subthreshold behavior. The model is suitable for incorporation into circuit simulators.
2011
This paper presents a compact model for the electrostatic potentials and the current characteristics of doped long-channel cylindrical surrounding-gate (SRG) MOSFETs. An analytical expression of the potentials is derived as a function of doping concentration. Then, the mobile charge density is calculated using the analytical expressions of the surface potential at the surface and the difference of potentials between the surface and the center of the silicon doped layer. Using the expression obtained for the mobile charge, a drain current expression is derived. Comparisons of the modeled expressions with the simulated characteristics obtained from the 3D ATLAS device simulator for the transfer characteristics, as well for the output characteristics, show good agreement within the practical range of gate and drain voltages and for doping concentrations ranging from 10 16 cm À3 to 5 Â 10 18 cm À3 .
Solid-State Electronics, 2007
An explicit current-voltage model for undoped double-gate MOSFETs based on an accurate analytic approximation to the carrier concentration is presented in this paper. An analytic approximation solution to the carrier (electron) concentration is derived from the Taylor expansion of the exact solution of the Poisson equation. This analytic approximation gives a highly accurate result of the electron concentration when compared with that evaluated by Newton-Raphson iterative. The resulting electron concentration is then coupled to the Pao-Sah current equation to produce an explicit current-voltage model for symmetric undoped double-gate MOSFETs. The model predictions have been extensively validated by numerical simulations.