scholarly journals Analysis of an Approximated Model for the Depletion Region Width of Planar Junctionless Transistors

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1436
Author(s):  
Arian Nowbahari ◽  
Avisek Roy ◽  
Muhammad Nadeem Akram ◽  
Luca Marchetti
Keyword(s):  
Numerical Simulations ◽  
Analytical Model ◽  
Threshold Voltage ◽  
Analytical Formula ◽  
Numerical Data ◽  
Maximum Error ◽  
Depletion Region ◽  
Comsol Multiphysics ◽  
Flat Band ◽  
Junctionless Transistors

In this paper, we investigate the accuracy of the approximated analytical model currently utilized, by many researchers, to describe the depletion region width in planar junctionless transistors (PJLT). The proposed analysis was supported by numerical simulations performed in COMSOL Multiphysics software. By comparing the numerical results and the approximated analytical model of the depletion region width, we calculated that the model introduces a maximum RMS error equal to 90 % of the donor concentration in the substrate. The maximum error is achieved when the gate voltage approaches the threshold voltage ( V t h ) or when it approaches the flat band voltage ( V F B ) of the transistor. From these results, we concluded that this model cannot be used to determine accurately the flat-band and the threshold voltage of the transistor, although it represents a straightforward method to estimate the depletion region width in PJLT. By using the approximated analytical model, we extracted an analytical formula, which describes the electron concentration at the ideal boundary of the depletion region. This formula approximates the numerical data extracted from COMSOL with a relative error lower than 1 % . The proposed formula is in our opinion, as useful as the formula of the approximated analytical model because it allows for estimating the position of the depletion region also when the drain and source terminals are not grounded. We concluded that the analytical formula proposed at the end of this work could be useful to determine the position of the depletion region boundary in numerical simulations and in graphical representations provided by COMSOL Multiphysics software.

scholarly journals Static Electromechanical Characteristic of a Three-Layer Circular Piezoelectric Transducer

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 222 ◽  
Author(s):  
Grzegorz Mieczkowski ◽  
Andrzej Borawski ◽  
Dariusz Szpica
Keyword(s):  
Piezoelectric Material ◽  
Analytical Model ◽  
Plate Theory ◽  
Piezoelectric Materials ◽  
Analytical Formula ◽  
Numerical Data ◽  
Passive Layer ◽  
Functional Features ◽  
Piezoelectric Disk ◽  
Electromechanical Characteristic

The paper presents research related to the functional features of a novel three-layer circular piezoelectric actuator/sensor. The outer layers of the transducer are made of non-piezoelectric material. The middle layer comprises two elements—a piezoelectric disk, and a ring made of non-piezoelectric material. The additional external passive layer has a very important function; it protects the transducer’s electrical components against damage caused by external factors. Also, if sparking on the transducer wires or electrodes occurs, this layer prevents fire. So far, there is no analytical model for such a transducer. Closed-form analytical equations are important tools for predicting and optimizing the operation of devices. Thus, using both the Plate Theory and constitutive equations of piezoelectric materials, an analytical formula describing transducer deflection as a function of electrical loads has been found (electromechanical characteristic of the transducer). In addition, it is worth noting that under certain assumptions, the developed analytical model can also be used for two-layer transducers. The tests carried out show satisfactory compliance of the results obtained through the developed solution with both literature data and numerical data. Moreover, based on the obtained analytical model, the effect of selected non-dimensional variables on the actuator performance has been examined. These parameters include dimensions and mechanical properties of both piezoelectric disk and passive plates and strongly influence the behavior of the transducer.

scholarly journals Analytical Model for the Channel Maximum Temperature in Ga2O3 MOSFETs

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Xiaole Jia ◽  
Haodong Hu ◽  
Genquan Han ◽  
Yan Liu ◽  
Yue Hao
Keyword(s):  
Thermal Conductivity ◽  
Thermal Behavior ◽  
Ambient Temperature ◽  
Numerical Simulations ◽  
Thermal Management ◽  
Power Density ◽  
Analytical Model ◽  
Maximum Temperature ◽  
Comsol Multiphysics ◽  
Increasing Temperature

AbstractIn this work, we proposed an accurate analytical model for the estimation of the channel maximum temperature of Ga2O3 MOSFETs with native or high-thermal-conductivity substrates. The thermal conductivity of Ga2O3 is anisotropic and decreases significantly with increasing temperature, which both are important for the thermal behavior of Ga2O3 MOSFETs and thus considered in the model. Numerical simulations are performed via COMSOL Multiphysics to investigate the dependence of channel maximum temperature on power density by varying device geometric parameters and ambient temperature, which shows good agreements with analytical model, providing the validity of this model. The new model is instructive in effective thermal management of Ga2O3 MOSFETs.

An Analytical Modeling and Performance Analysis of Graded Work Function Gate Recessed Channel SOI-MOSFET

2019 ◽  
Vol 9 (4) ◽  
pp. 504-511
Author(s):  
Sikha Mishra ◽  
Urmila Bhanja ◽  
Guru Prasad Mishra
Keyword(s):  
Analytical Model ◽  
Surface Potential ◽  
Threshold Voltage ◽  
Silicon On Insulator ◽  
Junction Depth ◽  
Short Channel ◽  
Soi Mosfet ◽  
Minimum Surface ◽  
Recessed Channel ◽  
The Impact

Introduction: A new analytical model is designed for Workfunction Modulated Rectangular Recessed Channel-Silicon On Insulator (WMRRC-SOI) MOSFET that considers the concept of groove gate and implements an idea of workfunction engineering. Methods: The impact of Negative Junction Depth (NJD) and oxide thickness (tox) are analyzed on device performances such as Sub-threshold Slope (SS), Drain Induced Barrier Lowering (DIBL) and threshold voltage. Results: The results of the proposed work are evaluated with the Rectangular Recessed Channel-Silicon On Insulator (RRC-SOI) MOSFET keeping the metal workfunction constant throughout the gate region. Furthermore, an analytical model is developed using 2D Poisson’s equation and threshold voltage is estimated in terms of minimum surface potential. Conclusion: In this work, the impact of Negative Junction Depth (NJD) on minimum surface potential and the drain current are also evaluated. It is observed from the analysis that the analog switching performance of WMRRC-SOI MOSFET surpasses RRC-SOI MOSFET in terms of better driving capability, high Ion/Ioff ratio, minimized Short Channel Effects (SCEs) and hot carrier immunity. Results are simulated using 2D Sentaurus TCAD simulator for validation of the proposed structure.

scholarly journals Inertial-particle accelerations in turbulence: a Lagrangian closure

2016 ◽  
Vol 798 ◽  
pp. 187-200 ◽  
Author(s):  
S. Vajedi ◽  
K. Gustavsson ◽  
B. Mehlig ◽  
L. Biferale
Keyword(s):  
Numerical Simulations ◽  
Numerical Data ◽  
Direct Numerical Simulations ◽  
Inertial Particles ◽  
Inertial Particle ◽  
Order Unity ◽  
Heavy Particles ◽  
Preferential Sampling ◽  
Closure Scheme ◽  
Light Particles

The distribution of particle accelerations in turbulence is intermittent, with non-Gaussian tails that are quite different for light and heavy particles. In this article we analyse a closure scheme for the acceleration fluctuations of light and heavy inertial particles in turbulence, formulated in terms of Lagrangian correlation functions of fluid tracers. We compute the variance and the flatness of inertial-particle accelerations and we discuss their dependency on the Stokes number. The closure incorporates effects induced by the Lagrangian correlations along the trajectories of fluid tracers, and its predictions agree well with results of direct numerical simulations of inertial particles in turbulence, provided that the effects induced by inertial preferential sampling of heavy/light particles outside/inside vortices are negligible. In particular, the scheme predicts the correct functional behaviour of the acceleration variance, as a function of $St$, as well as the presence of a minimum/maximum for the flatness of the acceleration of heavy/light particles, in good qualitative agreement with numerical data. We also show that the closure works well when applied to the Lagrangian evolution of particles using a stochastic surrogate for the underlying Eulerian velocity field. Our results support the conclusion that there exist important contributions to the statistics of the acceleration of inertial particles independent of the preferential sampling. For heavy particles we observe deviations between the predictions of the closure scheme and direct numerical simulations, at Stokes numbers of order unity. For light particles the deviation occurs for larger Stokes numbers.

Analytical model for predicting threshold voltage in submicrometer-channel MOSFET's

1985 ◽  
Vol 32 (9) ◽  
pp. 1890-1893 ◽  
Author(s):  
Ting-Wei Tang ◽  
Qian-Ling Zhang ◽  
D.H. Navon
Keyword(s):  
Analytical Model ◽  
Threshold Voltage

The effects of geometric offsets on the dynamic responses of a Scott—Russell amplifying mechanism with flexible hinges

2009 ◽  
Vol 223 (10) ◽  
pp. 2413-2423 ◽  
Author(s):  
C-M Chen ◽  
R-F Fung
Keyword(s):  
Numerical Simulations ◽  
Analytical Model ◽  
Dynamic Responses ◽  
Analytical Models ◽  
Dynamic Equations ◽  
Magnification Factor ◽  
Flexure Hinges ◽  
Magnification Factors ◽  
Straight Line ◽  
Deviation Factor

The dynamic equations of a micro-positioning Scott—Russell (SR) mechanism associated with two flexible hinges and an offset are developed to calculate output responses. Both rigid and flexible hinges are considered to explore the results. The main features in the kinematics of the SR mechanism are its displacement amplification and straight-line motion, which are widely needed in practical industries. The manufacturing inaccuracy of the SR mechanism definitely causes geometric offsets of flexure hinges, and affects displacement amplification and straight-line output motion. Analytical models based on kinematics and Hamilton's principle are derived to explore the variation of linearity ratio, magnification factor, and deviation factor due to various offsets and link lengths. From numerical simulations for the SR mechanism with various offsets of flexible hinges in the conditions of different link lengths, it is found that offsets of flexure hinges obviously affect the amplifying factor and linearity ratio, and appear to dominate the changes of magnification factors. Moreover, an analytical model is also used to predict magnification factors due to various offsets. Finally, some conclusions concerning the effects of offset on the performance of the SR mechanism are drawn.

An analytical model for anomalous threshold voltage behavior of short channel MOSFETs

1997 ◽  
Vol 41 (9) ◽  
pp. 1386-1388 ◽  
Author(s):  
Manoj K. Khanna ◽  
Maneesha ◽  
Ciby Thomas ◽  
R.S. Gupta ◽  
Subhasis Haldar
Keyword(s):  
Analytical Model ◽  
Threshold Voltage ◽  
Short Channel ◽  
Anomalous Threshold
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