scholarly journals Numerical Simulation of Nanoscale Double-Gate MOSFETs

10.14311/876 ◽  
2006 ◽  
Vol 46 (5) ◽  
Author(s):  
R. Stenzel ◽  
L. Müller ◽  
T. Herrmann ◽  
W. Klix

The further improvement of nanoscale electron devices requires support by numerical simulations within the design process. After a brief description of our SIMBA 2D/3D-device simulator, the results of the simulation of DG-MOSFETs are represented. Starting from a basic structure with a gate length of 30 nm, the model parameters were calibrated on the basis measured values from the literature. Afterwards variations in of gate length, channel thickness and doping, gate oxide parameters and source/drain doping were made in connection with numerical calculation of the device characteristics. Then a DG-MOSFET with a gate length of 15 nm was optimized. The optimized structure shows suppressed short channel behavior and short switching times of about 0.15 ps. 

Author(s):  
Hakkee Jung

Threshold voltage roll-off is analyzed for sub-10 nm asymmetric double gate (DG) MOSFET. Even asymmetric DGMOSFET will increase threshold voltage roll-off in sub-10 nm channel length because of short channel effects due to the increase of tunneling current, and this is an obstacle against the miniaturization of asymmetric DGMOSFET. Since asymmetric DGMOSFET can be produced differently in top and bottom oxide thickness, top and bottom oxide thicknesses will affect the threshold voltage roll-off. To analyze this, <em>thermal</em><em> </em>emission current and tunneling current have been calculated, and threshold voltage roll-off by the reduction of channel length has been analyzed by using channel thickness and top/bottom oxide thickness as parameters. As a result, it is found that, in short channel asymmetric double gate MOSFET, threshold voltage roll-off is changed greatly according to top/bottom gate oxide thickness, and that threshold voltage roll-off is more influenced by silicon thickness. In addition, it is found that top and bottom oxide thickness have a relation of inverse proportion mutually for maintaining identical threshold voltage. Therefore, it is possible to reduce the leakage current of the top gate related with threshold voltage by increasing the thickness of the top gate oxide while maintaining the same threshold voltage.


2018 ◽  
Vol 32 (15) ◽  
pp. 1850157 ◽  
Author(s):  
Yue-Gie Liaw ◽  
Chii-Wen Chen ◽  
Wen-Shiang Liao ◽  
Mu-Chun Wang ◽  
Xuecheng Zou

Nano-node tri-gate FinFET devices have been developed after integrating a 14 Å nitrided gate oxide upon the silicon-on-insulator (SOI) wafers established on an advanced CMOS logic platform. These vertical double gate (FinFET) devices with ultra-thin silicon fin (Si-fin) widths ranging from 27 nm to 17 nm and gate length down to 30 nm have been successfully developed with a 193 nm scanner lithography tool. Combining the cobalt fully silicidation and the CESL strain technology beneficial for PMOS FinFETs was incorporated into this work. Detailed analyses of [Formula: see text]–[Formula: see text] characteristics, threshold voltage [Formula: see text], and drain-induced barrier lowering (DIBL) illustrate that the thinnest 17 nm Si-fin width FinFET exhibits the best gate controllability due to its better suppression of short channel effect (SCE). However, higher source/drain resistance [Formula: see text], channel mobility degradation due to dry etch steps, or “current crowding effect” will slightly limit its transconductance [Formula: see text] and drive current.


Author(s):  
Ajay Kumar Singh

Purpose This study aims to develop a compact analytical models for undoped symmetric double-gate MOSFET based on carrier approach. Double-Gate (DG) MOSFET is a newly emerging device that can potentially further scale down CMOS technology owing to its excellent control of short channel effects, ideal subthreshold slope and free dopant-associated fluctuation effects. DG MOSFET is of two types: the symmetric DG MOSFET with two gates of identical work functions and asymmetric DG MOSFET with two gates of different work functions. To fully exploit the benefits of DG MOSFETs, the body of DG MOSFETs is usually undoped because the undoped body greatly reduces source and drain junction capacitances, which enhances the switching speed. Highly accurate and compact models, which are at the same time computationally efficient, are required for proper modeling of DG MOSFETs. Design/methodology/approach This paper presents a carrier-based approach to develop a compact analytical model for the channel potential, threshold voltage and drain current of a long channel undoped symmetric DG MOSFETs. The formulation starts from a solution of the 2-D Poisson’s equation in which mobile charge term has been included. The 2-D Poisson’s equation in rectangular coordinate system has been solved by splitting the total potential into long-channel (1-D Poisson’s equation) and short-channel components (remnant 2-D differential equation) in accordance to the device physics. The analytical model of the channel potential has been derived using Boltzmann’s statistics and carrier-based approach. Findings It is shown that the metal gate suppresses the center potential more than the poly gate. The threshold voltage increases with increasing metal work function. The results of the proposed models have been validated against the Technology Computer Aided Design simulation results with close agreement. Originality/value Compact Analytical models for undoped symmetric double gate MOSFETs.


Aggressive scaling of Metal-oxide-semiconductor Field Effect Transistors (MOSFET) have been conducted over the past several decades and now is becoming more intricate due to its scaling limit and short channel effects (SCE). To overcome this adversity, a lot of new transistor structures have been proposed, including multi gate structure, high-k/metal gate stack, strained channel, fully-depleted body and junctionless configuration. This paper describes a comprehensive 2-D simulation design of a proposed transistor that employs all the aforementioned structures, named as Junctionless Strained Double Gate MOSFETs (JLSDGM). Variation in critical design parameter such as gate length (Lg ) is considered and its impact on the output properties is comprehensively investigated. The results shows that the variation in gate length (Lg ) does contributes a significant impact on the drain current (ID), on-current (ION), off-current (IOFF), ION/IOFF ratio, subthreshold swing (SS) and transconductance (gm). The JLSDGM device with the least investigated gate length (4nm) still provides remarkable device properties in which both ION and gm(max) are measured at 1680 µA/µm and 2.79 mS/µm respectively


2020 ◽  
Vol 16 (2) ◽  
Author(s):  
Safayet Ahmed ◽  
Md. Tanvir Hasan

The effect of oxide thickness (EOT) on GaN-based double gate (DG) MOSFETs have been explored for low power switching device. The gate length (LG) of 8 nm with 4 nm underlap is considered. The device is turned off and on for gate voltage (VGS) of 0 V and 1 V, respectively. The effective oxide thickness (EOT) is varied from 1 nm to 0.5 nm and the device performance is evaluated. For EOT = 0.5 nm, the OFF-state current (IOFF), subthreshold slope (SS) and drain induced barrier lowering (DIBL) are obtained 2.97×10-8 A/μm, 69.67 mV/dec and 21.753 mV/V, respectively. These results indicate that, it is possible to minimize short channel effects (SCEs) by using smaller value of EOT.


2005 ◽  
Vol 04 (05n06) ◽  
pp. 1021-1024 ◽  
Author(s):  
ABHINAV KRANTI ◽  
TSUNG MING CHUNG ◽  
JEAN-PIERRE RASKIN

A detailed analysis of static and dynamic characteristics of deep submicron double and single gate SOI MOSFETs is presented, based on 2D numerical simulations for high frequency analog applications. Results show that although DG MOSFET offers excellent performance with respect to short channel immunity and higher transconductance, it offers nearly two times the value of gate-to-source capacitance as compared to SG devices, thus limiting the cut-off frequency at higher gate voltages. At ultra short channel lengths and low gate overdrive voltages, DG devices show a significant improvement in cut-off frequency compared to SG devices, thus presenting DG nanotransistors as potential candidates for analog microwave applications.


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