2018
In this paper, a graded channel doping paradigm is proposed to improve the nanoscale double gate junctionless DGJL MOSFET electrical performance. A careful mechanism study based on numerical investigation and a performance comparison between the proposed and conventional design is carried out. The device figures-of-merit, governing the switching and leakage current behavior are investigated in order to reveal the transistor electrical performance for ultra-low power consumption. It is found that the channel doping engineering feature has a profound implication in enhancing the device electrical performance. Moreover, the impact of the high-k gate dielectric on the device leakage performance is also analyzed. The results show that the proposed design with gate stacking demonstrates superior ION/IOFF" id="MathJax-Element-1-Frame" role="presentation" style="position:relative;" tabindex="0">ION/IOFF ratio and lower leakage current as compared to the conventional counterpart. Our analysis highlights the good ability of the proposed design including a high-k gate dielectric for the reduction of the leakage current. These characteristics underline the distinctive electrical behavior of the proposed design and also suggest the possibility for bridging the gap between the high derived current capability and low leakage power. This makes the proposed GCD-DGJL MOSFET with gate stacking a potential alternative for high performance and ultra-low power consumption applications.
In this work, versatile CdS/Cu 2 ZnSnS 4 (CZTS) solar cell designs based on intermediate metallic sub-layers (Au, Ti, and Ag) engineering are proposed for enhancing light-scattering behavior and reducing recombination losses. The idea behind this work is to generate optical confinement regions in the CZTS absorber layer to achieve an improved absorption and appropriate antireflection effects. Moreover, the ultra-thin metal at the CZTS/Mo interface can be helpful for reducing the series resistance, where it behaves like a blocking layer for the Sulfur diffusion. We further combine the proposed designs with Particle Swarm Optimization (PSO)-based approach to achieve broadband absorption and boost the conversion efficiency. It is found that the optimized design with Ti sub-layer improves the CZTS solar cell properties, where it yields 31% improvement in short-circuit current and 60% in the power efficiency over the conventional one. Therefore, the optimized designs provide the opportunity for bridging the gap between improving the optical behavior and reducing the recombination losses.
In this paper, channel doping engineering aspect is proposed as a new way to improve the junctionless Gate All Around (GAA) MOSFET performance for digital and analog applications. The amended channel doping consists of a lateral graded profile, where the channel is divided into two regions with different doping levels. Analytical approaches for the drain current, leakage power, digital and small signal parameters are developed incorporating the impact of graded channel doping (GCD) paradigm on the device electrical behavior. Exhaustive study based on a performance comparison between the proposed structure and the conventional one is carried out, where the proposed design exhibits a good capability in improving the overall device figures-of-merit (FoMs), governing the leakage and the analog performance. More importantly, Particle Swarm Optimization (PSO) approach is proposed as a metaheuristic technique to boost the device performance through carefully adjusting the design parameters of the proposed GCD feature. It is found that the optimized design outperforms considerably the conventional counterpart and enable making wise trade-offs, where an enhancement of 300% in the I ON /I OFF ratio, 482% in the intrinsic gain, and 340% in the cut-off frequency has been reached. Besides, the proposed design provides a sufficient capability for suppression of the leakage effects. The obtained results underline the distinctive property of the proposed design for bridging the gap between high analog and digital performances with ultra-low power consumption. This makes the proposed design a potential alternative for ultra-low power and high electrical performance applications.
In this paper, a new optically controlled tunneling field effect transistor (OC-TFET) based on SiGe/Si/Ge hetero-channel is proposed to improve optical commutation speed and reduce power consumption. An exhaustive study of the device switching behavior associated with different hetero-channel structures has been carried out using an accurate numerical simulation. Moreover, a new figure of Merit (FoM) parameter called optical swing factor that describes the phototransistor optical commutation speed is proposed. We demonstrate that the band-to-band tunneling effect can be beneficial for improving the device optical commutation speed. The impact of the Ge mole fraction of the SiGe source region on the device FoMs is investigated. It is found that the optimized design with 40% of Ge content offers the opportunity to overcome the trade-off between ultrafast and very sensitive photoreceiver performance, where it yields 48 mV/dec of optical swing factor and 155 dB of I ON /I OFF ratio. An overall performance comparison between the proposed OC-TFET device and the conventional designs is performed, where the proposed structure ensures high optical detectivity for very low optical powers (sub-1pW) as compared to that of the conventional counterparts. Therefore, the proposed OC-TFET provides the possibility for bridging the gap between improved optical commutation speed and reduced power consumption, which makes it a potential alternative for high-performance inter-chip data communication applications.
A continuous and accurate model based on the two-dimensional (2D) potential solution of a tunnel field-effect transistor (TFET) with undoped vertical surrounding-gate (VSG) structure is proposed. Both ambipolarity and dual modulation effects are included to obtain a more accurate analytical model, whose validity is demonstrated by comparison with two-dimensional numerical simulations using ATLAS-2D. The continuity of the proposed model enables extraction of analog/radiofrequency (RF) parameters and device figures of merit. Moreover, the effect of introducing a high-κ" id="MathJax-Element-1-Frame" role="presentation" style="position:relative;" tabindex="0">κ layer on the gate oxide in improving the behavior of the VSG-TFET is explored for use in high-performance analog/RF applications. The proposed continuous analytical model can be easily implemented in commercial simulators to study and investigate VSG-TFET-based nanoelectronic circuits.
In this paper, a new nanoscale double-gate junctionless tunneling field-effect transistor (DG-JL TFET) based on a Si1−xGex/Si/Ge heterojunction (HJ) structure is proposed to achieve an improved electrical performance. The effect of introducing the Si1−xGex material at the source side on improving the subthreshold behavior of the DG-JL TFET and on suppressing ambipolar conduction is investigated. Moreover, the impact of the Ge mole fraction in the proposed Si1−xGex source region on the electrical figures of merit (FoMs) of the transistor, including the swing factor and the ION/IOFF ratio is analyzed. It is found that the optimized design with 60 atom % of Ge offers improved switching behavior and enhanced derived current capability at the nanoscale level, with a swing factor of 42 mV/dec and an ION/IOFF ratio of 115 dB. Further, the scaling capability of the proposed Si1−xGex/Si/Ge DG-HJ-JL TFET structure is investigated and compared to that of a conventional Ge-DG-JL TFET design, where the optimized design exhibits an improved switching behavior at the nanoscale level. These results make the optimized device suitable for designing digital circuit for high-performance nanoelectronic applications.
In this work, we present a comprehensive investigation of JL-GAA MOSFET including degradation-related ageing effects to study the nanoscale JL-GAA MOSFET reliability against the ageing phenomenon. A quantitative analysis of the device reliability behavior is carried out, in order to show the impact of the ageing effects on the device performance for digital applications. Moreover, the effect of the stress time on the device subthreshold behavior including the threshold voltage, DIBL and swing factor is elucidated, where the degradation related-ageing effects is represented by a new current generator in the opposite direction that describes the exponential degradation of the current as function of the stress time. Further, the role of introducing a high-k layer on the gate oxide in improving the JL-GAA MOSFET immunity against the degradation-related ageing effects is analyzed, where the proposed structure exhibits an excellent immunity against the ageing effects. In order to show the impact of the proposed approach on the nanoelectronic circuits designing, the developed model has been implemented to study the performance behavior of voltage amplifier circuit including degradation-related ageing effects. Therefore, the proposed approach can offer new insights regarding the investigation and simulation of the nanoelectronic circuits including the degradation-related ageing effects.
This paper presents a new nanoforce sensor based on a suspended carbon nanotube gate field-effect transistor. To do so, a numerical investigation of Suspended Gate Silicon-on-Insulator MOSFET (SG-SOIMOSFET) is carried out using ATLAS 2D simulator. Based on the relationship between the nanotube’s deflection and the applied force, a comprehensive study of the proposed nanoforce sensor behavior is performed. Moreover, we describe the evolution of the drain current characteristics as a function of the applied force while examining the influence of capacity variation of the insulating gate on the drain current in the saturation region. It is found that the sensor has a good sensitivity of 230.68 ln(A)/pN. Our second contribution in this paper is to develop a model based on artificial neural networks (ANNs). We successfully integrate our neural model of nanoforce sensor as a new component in the ORCAD-PSPICE electric simulator library; this component must accurately express the behavior of the sensor. A second model based on neural networks, which deals with correction and linearization of the sensor output signal, is designed and implemented into the same simulator. The proposed device can be considered as a potential alternative for CMOS-based nanoforce sensing.
In this work, a new ultraviolet optically-controlled field-effect transistor (UV-OCFET) based on ZnMgO photosensitive gate with graded band-gap aspect is proposed and investigated using a comprehensive analytical modeling. The impact of different band-gap profiles on the phototransistor figure of merits (FoMs) is analyzed. Our study demonstrates that the use of ZnMgO with a graded band-gap profile can generate an electric field in the photosensitive layer, which leads to achieve the dual role of effective electron/hole pair separation and lower recombination losses. Moreover, increasing the Mg content progressively not only enables a strong UV-light absorption but also allows achieving a high optical sensitivity for very low optical powers (sub-1pW). The particle-swarm optimization approach is exploited to boost the phototransistor FoMs by optimizing the sensor design parameters and the ZnMgO band-gap profile. It is found that the optimized structure exhibits superior optical characteristics as compared to those of the conventional UV-photodetectors. Therefore, the optimized ZnMgO UV-OCFET with graded band-gap paradigm pinpoints a new path toward recording an ultrasensitive phototransistor compatible with CMOS modern technology. This makes it a potential alternative for high-performance and low-energy consumption chip-level UV-communication and monitoring applications.
In this paper, the role of introducing an intermediate Indium Tin Oxide (ITO) thin-film in improving the Au/Si Schottky Barrier Diodes (SBDs) electrical performance is experimentally analyzed. The Au/ITO/Si/Au structures with different ITO thicknesses were fabricated using RF magnetron sputtering technique. The current-voltage (I-V) characteristics of the investigated structures are analyzed, where the device electrical parameters are extracted. It is found that the introduced ITO thin-film has a significant impact in reducing the ideality factor (n=1.25), the interfacial defects (Nss=1.5×1012 eV−1cm−2) and the series resistance (Rs=32Ω). Our study demonstrates that the use of ITO intermediate thin-film can generate minority carrier injection effects, which lead to achieve the dual role of enhanced derived current and lower series resistance. Moreover, the structure thermal stability behavior is investigated and compared with those of the conventional design in order to reveal the device reliability against the thermal variation. Furthermore, the effect of the annealing on the device thermal stability is also analyzed. Our investigation shows that the annealed structure provides the possibility for avoiding the degradation related-heating effects. Therefore, the proposed Au/ITO/Si/Au structure offers the opportunity for bridging the gap between achieving superior electrical performance and enhanced thermal stability. The obtained results may facilitate the design of high-performance SBDs for sensing and microelectronic applications.
The disturbances are the significant issue for the trajectory tracking of mobile robots. Therefore, an adequate control law is presented in this paper and this one is based on Global Terminal Sliding Mode (GTSM) with fuzzy control. This control law aims to guarantee the avoidance of the kinematic disturbances which are injected in the angular and linear velocities, respectively. Moreover, the dynamic model based on exponential reaching law is presented to avoid the uncertainties. The control law provides the asymptotic stability by taking into account the fuzzy rules and Lyapunov theory. Thus, the chattering phenomenon should be avoided. The simulation works prove the robustness of the proposed control law by considering the disturbances function and the robot can follow the desired trajectories.
This paper presents a new approach in the field of trajectory tracking for nonholonomic mobile robot in presence of disturbances. The proposed control design is constructed by a kinematic controller, based on PD sliding surface using fuzzy sliding mode for the angular and linear velocities disturbances, in order to tend asymptotically the robot posture error to zero. Thereafter a dynamic controller is presented using as a sliding surface design, a fast terminal function (FTF) whose parameters are generated by a genetic algorithm in order to converge the velocity errors to zero in finite time and guarantee the asymptotic stability of the system using a Lyapunov candidate. The elaborated simulation works in the case of different trajectories confirm the robustness of the proposed approach.
The main purpose of this paper is to integrate fuzzy logic technique and backstepping synthesis to sliding mode control to develop a Fuzzy Backstepping-Sliding Mode Controller (FBSMC) to resolve the problem of altitude and attitude tracking control of unmanned quadrotor systems under large external disturbances. First, a backstepping-sliding mode control for quadrotor is introduced. Moreover, a fuzzy logic system is employed to adapt the unknown switching gains to eliminate the chattering phenomenon induced by switching control on the conventional Backstepping-Sliding Mode Controller (BSMC). The dynamical motion equations are obtained by Euler-Newton formalism. The stability of the system is guaranteed in the sense of the Lyapunov stability theorem. Simulation results are carried out using Matlab/Simulink environment to illustrate the effectiveness and robustness of the proposed controller.
In this paper a dynamic tracking control of mobile robot using neural network global fast sliding mode (NN-GFSM) is presented. The proposed strategy combines two control approaches, kinematic control and dynamic control. The laws of kinematic control are based on GFSM in order to determine the adequate velocities for the system stability in finite time. The dynamic controller combines two control techniques, the GFSM to stabilize the velocities errors, and a neural network controller in order to approximate a nonlinear function and to deal the disturbances. This dynamic controller allows the robots to follow the desired trajectory even in the presence of disturbances. The designed controller is dynamically simulated by using Matlab/ Simulink and the simulations results show the efficiency and robustness of the proposed control strategy.
A complete parametric study of stacked rectangular microstrip patches printed on non-magnetic isotropic substrate is performed. The numerical results are obtained by applying the method of moments to the electric field integral equations. Detailed closed-form expressions of Green's functions are presented. The new results found indicate that, the lower resonant frequency is mainly determined by the patch etched on the thicker layer. The layer having the higher permittivity defines which resonance is mainly determined by the bottom patch, either the upper resonance if the upper layer has the higher permittivity, or the lower resonance in opposite case. All these results offer better understanding and thus a better control of the dual-band operating of the microstrip antenna. Therefore, a proper choice of the antenna parameters becomes possible in order to obtain the desired functional characteristics.
In this paper, the resonant frequencies, quality factors and bandwidths of high Tc superconducting circular microstrip patches in the presence of a dielectric superstrate loading have been studied using Galerkin testing procedure in the Hankel transform domain. The exact Green's function of the grounded dielectric slab is used to derive an electric field integral equation for the unknown current distribution on the circular disc. Thus, surface waves, as well as space wave radiation, are included in the formulation. London's equations and the two-fluid model of Gorter and Casimir are used in the calculation of the complex surface impedance of the superconducting circular disc. Galerkin testing is used in the resolution of the electric field integral equation. Two solutions using two different basis sets to expand the unknown disk currents are developed. The first set of basis functions used is the complete set of transverse magnetic and transverse electric modes of a cylindrical cavity with magnetic side walls. The second set of basis functions used employ Chebyshev polynomials and enforce the current edge condition. The computed values for a wide range of variations of superstrate thickness and dielectric constant are compared with different theoretical and experimental values available in the open literature, showing close agreement. Results are showing that the superstrate parameters should always be kept into account in the design stage of the superconducting microstrip resonators.
Spectral domain formulation is provided for the analysis of rectangular stacked patches printed on a substrate characterized by dielectric and magnetic uniaxial anisotropy. Detailed analytical expressions of the dyadic Green’s functions are derived. Galerkin’s procedure is applied to solve the electric field integral equations, and the resonance characteristics are determined by solving the characteristic equation. Numerical results show that the influence of the magnetic anisotropy on the resonant frequencies is highly dependent on the permeability of the medium, where for a non-magnetic medium, the impact of the existing anisotropy was found negligible. However, for a magnetic medium, the anisotropy has a large impact on the resonant frequencies. Moreover, the influence of each of the components of the permeability tensor has been also reported.
This work is mainly on the detection of the bulk acoustic waves (BAWs), where we have compared two Lithium Niobate cuts (Y-Z and Y-X), during the propagation of the acoustic microwaves in the piezoelectric LiNbO3-substrate. In this paper, we have used the classification by Probabilistic Neural Network (PNN) as a tool for numerical analysis in which we classify all the values of the real and imaginary parts of the attenuation coefficient for the propagation velocity. This analysis can allow us to demonstrate the best possibility in utilization for the BAW generation. This study will be very interesting in modeling and realization of acoustic wave devices (ultrasound) based on the propagation of acoustic microwaves.
The estimation of the junction temperature (Tj) is very important factor for improving the reliability and efficiency of the power electronic converters. A new electro-thermal (ET) model of low voltage power MOSFET is described in this paper. The electro-thermal model allows fast estimation of the junction temperature, based on the transient thermal impedances (Zth) using the (RC) Foster thermal network model and total power losses. The parameters of the (RC) Foster thermal network model are extracted from the data provided by the manufacturer’s datasheet using particle swarm optimization (PSO) method. Moreover, a dc/dc Buck converter is also analyzed by simulation to evaluate the electro-thermal model. The simulation results indicate a good agreement between the proposed model and manufacturer’s data. Finally, the electro-thermal (ET) model simulation using this (RC) Foster thermal network model shows a reasonable accuracy for estimating the junction temperature in a Dc/Dc buck converter.
