N. Lakhdar

Analytical analysis of nanoscale multiple gate MOSFETs including effects of hot-carrier induced interface charges

As the channel length rapidly shrinks down to the nanoscale regime, the multiple gate MOSFETs structures have been considered as potential candidates for a CMOS device scaling due to its good short-channel-effects (SCEs) immunity. Therefore, in this work we investigate the scaling capability of Double Gate (DG) and Gate All Around (GAA) MOSFETs using an analytical analysis of the two dimensional Poisson equation in which the hot-carrier induced interface charge effects have been considered. Basing on this analysis, we have found that the degradation becomes more important when the channel length gets shorter, and the minimum surface potential position is affected by the hot-carrier induced localized interface charge density. Using this analysis, we have studied the scaling limits of DG and GAA MOSFETs and compared their performances including the hot-carrier effects. Our obtained results showed that the analytical analysis is in close agreement with the 2-D numerical simulation over a wide range of devices parameters. The proposed analytical approach may provide a theoretical basis and physical insights for multiple gate MOSFETs design including the hot-carrier degradation effects.

A Two‐Dimensional Numerical Analysis of Subthreshold Performances for Double‐Gate GaN‐MESFETs

In this paper, a new deep submicron double‐gate (DG) GaN‐MESFET structure and its 2‐D numerical model have been proposed, investigated and expected to suppress the short‐ channel‐effects (SCEs) and improve the subthreshold behavior for deep submicron GaN‐MESFET‐based applications. The models have been used to predict and compare the performances of downscaled DG and conventional GaN‐MESFETs, where the comparison of device architectures shows that the proposed DG GaN‐Based MESFET exhibits a superior performance with respect to the conventional MESFET both in terms of threshold voltage and DIBL (Drain Induced Barrier Lowering) effect in deep submicron domain. The obtained results make (DG) GaN‐MESFET a promising candidate for future MESFET‐based circuits.

New optimized Dual-Material (DM) gate design to improve the submicron GaN-MESFETs reliability in subthreshold regime

Abstract In this paper, new Dual-Material-gate (DM) concept and optimization approach are proposed to improve the device immunity against the hot carrier and short channel effects (SCEs), and optimize the subthreshold electrical performance of the submicron Gallium Nitride (GaN)-MESFET. The 2D analytical analysis includes the modeling of the channel potential, subthreshold swing, threshold voltage, Drain-Induced Lowering Barrier (DIBL) and parasitic resistances. The influence of gate length and the work function of each gate region on subthreshold behavior was investigated using the developed analytical models. The developed analytical approaches are verified and validated by the good agreement found with the 2D numerical simulations for wide range of device parameters and bias conditions. The presented compact models are used to formulate the different objective functions, which are the pre-requisite of multi-objective genetic algorithms optimization, which will be used to optimize the device subthreshold performances. The optimized design can alleviate the critical problem and further improve the immunity of SCEs of submicron GaN-MESFET-based digital circuits for low power and high speed applications.

An accurate organic solar cell parameters extraction approach based on the illuminated I-V characteristics for double diode modeling

In this paper, new electrical scheme modeling approach is proposed to extract the electrical parameters of the organic solar cells. These parameters such as shunt resistance, series resistance, saturation current, ideality factors, photo-current density and open-circuit voltage of the device have been ascertained using the Trust-Region Method (TR) for the double exponential solar cell model. We determine the seven solar cell parameters of the double diode circuit model using only the measured current-voltage data under illumination. The results of proposed approach demonstrate that it allows obtaining precise extracted parameters, which is confirmed by the good agreements between the fitted I-V curve and the experimental results. The proposed approach can be used to design the photovoltaic panels for an accurate solar power modeling.

An approach based on particle swarm computation to study the electron mobility in wurtzite GaN

The properties of gallium nitride (GaN) make it a promising material for a variety of different electronic and optoelectronic devices. GaN has a wide direct bandgap and a resulting high breakdown field. Further progress in the development, design and optimization of GaN-based devices necessarily requires new theory and modeling techniques that capture the physics of electron transport accurately and efficiently. So, the objective of this work is to provide an optimized analytical model for low- and high-field electron mobility in wurtzite (hexagonal) GaN in wide temperature and concentration ranges basing on the particle swarm optimization (PSO) algorithm. A Monte Carlo transport simulations developed in this work has been evaluated and serve as the basis for the model development. The proposed model describes the dependence of the mobility on carrier concentration, temperature, and electric field. Good agreement between our results and measured data has been obtained. Thus, the presented mobility models can be used in device simulations to design and optimize different GaN device structures.

Parameter determination of Schottky -barrier diode model using genetic algorithm

In this paper, genetic algorithm (GA) has been applied to extract the Schottky-barrier height, ideality factor and series resistance, this new method presents the effect of wide range temperature of Schottky-barrier diode (SBD) model using forward current-voltage (I–V) characteristics, is discussed. The results found was compared with experimental current-voltage data, it has been confirmed that the proposed method can obtain higher parameter precision with better computational efficiency more easily than other methods.

An analytical threshold voltage model to study the scaling capability of deep submicron double-gate GaN-MESFETs

In this work, a deep submicron double-gate (DG) Gallium Nitride (GaN)-MESFET design and its 2-D threshold analytical model have been proposed and expected to suppress the short-channel-effects for deep submicron GaN-MESFET-based low power applications. The model predicts that the threshold voltage is greatly improved in comparison with the conventional Single-Gate GaN-MESFET. The developed approaches are verified and validated by the good agreement found with the 2D numerical simulations for wide range of device parameters and bias conditions. DG GaN-MESFET can alleviate the critical problem and further improve the immunity of short-channel-effects of GaN-MESFET-based circuits in the low power deep submicron devices.

Modeling of submicron triple material GaAs MESFET including the effect of third region length for microwave frequency applications

This work presents a study based on the modeling of Triple Material (TM) Gallium Arsenide (GaAs) MESFET. The proposed structure is used to minimize the short channel effects and enhance the device performance for microwave frequency applications. Different device characteristics like I-V and microwave characteristics incorporating the effect of the third region length of submicron TM GaAs MESFET are investigated. Therefore, the device performance has been evaluated in order to show the influence of the third region length on the GaAs MESFETs-based gate engineering. The proposed model is in excellent accord with 2-D device simulator called ATLAS from SILVACO. The obtained results demonstrate that TM GaAs MESFET presents an alternative solution to designer for high frequency applications.

An analytical model for submicron dual material gate GaNMESFET including the temperature effects

In this paper, a temperature dependent analytical model of submicron Dual Material gate (DM) Gallium Nitride (GaN) MESFET suitable for high power applications is described. The model takes into account the effect of various temperature dependent device parameters in order to develop an accurate current-voltage model of the device under various high temperature (300K-500K) conditions. The model is then extended to evaluate the temperature dependence of transconductance and output conductance. The obtained results have been verified by its good agreement with 2D numerical simulations.

Performance enhancement of ZnTeO solar cell by optimizing physical and geometrical parameters

In this paper, a physics-based model for various I-V characteristics and efficiency of intermediate band solar cell (IBSC) are developed. The model includes important parameters effects like absorption coefficient constants and energy level. Therefore, an approach based on Genetic Algorithms for increasing the photovoltaic conversion of the IBSC-based design is proposed in order to study and improve electrical behavior of the device. Our GA-based approach exhibits a significant improvement compared to analytical results found in literature providing guidance for the device design for high-cell performances.