This document summarizes a simulation study on the physical scaling limits of FinFET structures. It analyzes the scaling limits of double gate underlap and triple gate overlap FinFET structures using 2D and 3D computer simulations. Key findings include:
1) For double gate FinFETs, DIBL and SS increase abruptly when the ratio of gate length to fin thickness (L/Tfin) goes below 1.5, limiting scaling.
2) For triple gate FinFETs, both fin thickness and height can control short channel effects, but fin thickness is found to be a more dominant parameter. DIBL and SS increase as the ratio of effective gate length to fin thickness (Leff/Tfin) decreases
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
5164 2015 YRen Two-Dimensional Field Effect TransistorsYi Ren
This document provides an introduction to two-dimensional field effect transistors (2D FETs). It first discusses the limitations of conventional FETs as their size is reduced according to Moore's Law. 2D FETs are proposed as a way to continue increasing transistor density by using atomically thin 2D materials as the channel layer. The document then discusses properties of graphene and transition metal dichalcogenides, which are common materials used in 2D FET channels. Finally, examples of 2D FETs using MoS2 and other materials as the channel layer are described.
CROSSTALK MINIMIZATION FOR COUPLED RLC INTERCONNECTS USING BIDIRECTIONAL BUFF...VLSICS Design
Crosstalk noise is often induced in long interconnects running parallel to each other. There is a need to
minimize the effect of these crosstalk noise so as to maintain the signal integrity in interconnects. In this
paper crosstalk noise is minimized using various techniques such as repeater (bidirectional buffer)
insertion along with shielding, skewing and shielding & skewing simultaneously. With the help of these
techniques crosstalk noise is controlled to a great extent in long interconnects. Pre-layout and Post-layout
simulations for crosstalk are carried out for these techniques at 180nm technology node using Cadence
EDA tools. The influences of these techniques are analyzed and it is found that crosstalk is reduced up to
32 % with repeater insertion, 47% with skewing, 58% with shielding and 81% with skewing & shielding
simultaneously
Review of Fin FET Technology and Circuit Design ChallengesIJERA Editor
Considering the difficulties in planar CMOS transistor scaling to secure an acceptable gate to channel control
FinFET based multi-gate (MuGFET) devices have been proposed as a technology option for replacing the
existing technology. The desirability of FinFET that it’s operation principle is same as CMOS process. This
permits to lengthening the gate scaling beyond the planar transistor limits, sustaining a steep subthreshold slope,
better performance with bias voltage scaling and good matching due to low doping concentration in the channel.
There are, still, several challenges and limitations that FinFET technology has to face to be competitive with
other technology options: Fin shape, pitch, isolation, doping, crystallographic orientation and stressing as well as
device parasitic, performance and patterning approaches will be discussed.
A BUS ENCODING TO REDUCE CROSSTALK NOISE EFFECT IN SYSTEM ON CHIPVLSICS Design
This paper proposes a new bus coding scheme for reducing the crosstalk in System on chip(soc). As circuit geometries become smaller, wire interconnections become closer together and taller, thus increasing the cross-coupling capacitance between nets. At the same time, parasitic capacitance to the substrate becomes less as interconnections become narrower, and cell delays are reduced as transistors become smaller. With circuit geometries at 0.25 micron and above, substrate capacitance is usually the dominant effect. However, with geometries at 0.18 micron and below, the coupling capacitance between nets becomes significant, making crosstalk analysis increasingly important for accurate timing analysis. We show experimentally that the proposed codes allow reducing crosstalk delay by at least 14% based on available data.
EFFECT OF EQUAL AND MISMATCHED SIGNAL TRANSITION TIME ON POWER DISSIPATION IN...VLSICS Design
High density chips have introduced problems like crosstalk noise and power dissipation. The mismatching in transition time of the inputs occurs because different lengths of interconnects lead to different parasitic values. This paper presents the analysis of the effect of equal and unequal (mismatched) transition time of inputs on power dissipation in coupled interconnects. Further, the effect of signal skew on transition time is analysed. To demonstrate the effects, a model of two distributed RLC lines coupled capacitively and inductively is taken into consideration. Each interconnect line is 4mm long and terminated by capacitive load of 30fF. The analysis is carried out for simultaneously switching lines. The results are obtained through SPICE simulations and waveforms are generated.
The performance based analysis for typical Gaussian and Gaussian-Halo Doped Double Gate MOSFETs
in conjunction with Normal Doped DG MOSFETs, for which different parameters such as Oxide Thickness,
Ambient Temperature, Gate Material Work Function and Substrate Doping Concentration is varied. This
analysis has been carried out using a TCAD Lab simulation.. From the results obtained, it will be quite
clear that the sub-threshold leakage current of the Gaussian and Gaussian-Halo Doped Double Gate Metal
Oxide Semiconductor FET is relatively lesser. Furthermore the results have been plotted with different
Drain voltage values to enhance the understanding of the physics behind various Doping Profiles in
Double Gate MOSFET. Finally the results has been obtained, analysed and compared. The Possession of
higher Drain current Performance is very acceptable through the rigorous analysis using a TCAD Lab.
Performance Analysis of Double Hetero-gate Tunnel Field Effect TransistorIDES Editor
The document presents a double gate tunnel field effect transistor (TFET) with a hetero gate dielectric and low band gap material. Simulation results show the proposed device has higher on current, lower ambipolar current, and steeper subthreshold slope compared to a conventional silicon double gate TFET. Scaling the device provides better performance with negligible threshold voltage roll-off and reduced Miller capacitance. The hetero gate dielectric and low band gap material allow for improved tunneling probability and sharp subthreshold swing, making the device promising for low power applications.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
5164 2015 YRen Two-Dimensional Field Effect TransistorsYi Ren
This document provides an introduction to two-dimensional field effect transistors (2D FETs). It first discusses the limitations of conventional FETs as their size is reduced according to Moore's Law. 2D FETs are proposed as a way to continue increasing transistor density by using atomically thin 2D materials as the channel layer. The document then discusses properties of graphene and transition metal dichalcogenides, which are common materials used in 2D FET channels. Finally, examples of 2D FETs using MoS2 and other materials as the channel layer are described.
CROSSTALK MINIMIZATION FOR COUPLED RLC INTERCONNECTS USING BIDIRECTIONAL BUFF...VLSICS Design
Crosstalk noise is often induced in long interconnects running parallel to each other. There is a need to
minimize the effect of these crosstalk noise so as to maintain the signal integrity in interconnects. In this
paper crosstalk noise is minimized using various techniques such as repeater (bidirectional buffer)
insertion along with shielding, skewing and shielding & skewing simultaneously. With the help of these
techniques crosstalk noise is controlled to a great extent in long interconnects. Pre-layout and Post-layout
simulations for crosstalk are carried out for these techniques at 180nm technology node using Cadence
EDA tools. The influences of these techniques are analyzed and it is found that crosstalk is reduced up to
32 % with repeater insertion, 47% with skewing, 58% with shielding and 81% with skewing & shielding
simultaneously
Review of Fin FET Technology and Circuit Design ChallengesIJERA Editor
Considering the difficulties in planar CMOS transistor scaling to secure an acceptable gate to channel control
FinFET based multi-gate (MuGFET) devices have been proposed as a technology option for replacing the
existing technology. The desirability of FinFET that it’s operation principle is same as CMOS process. This
permits to lengthening the gate scaling beyond the planar transistor limits, sustaining a steep subthreshold slope,
better performance with bias voltage scaling and good matching due to low doping concentration in the channel.
There are, still, several challenges and limitations that FinFET technology has to face to be competitive with
other technology options: Fin shape, pitch, isolation, doping, crystallographic orientation and stressing as well as
device parasitic, performance and patterning approaches will be discussed.
A BUS ENCODING TO REDUCE CROSSTALK NOISE EFFECT IN SYSTEM ON CHIPVLSICS Design
This paper proposes a new bus coding scheme for reducing the crosstalk in System on chip(soc). As circuit geometries become smaller, wire interconnections become closer together and taller, thus increasing the cross-coupling capacitance between nets. At the same time, parasitic capacitance to the substrate becomes less as interconnections become narrower, and cell delays are reduced as transistors become smaller. With circuit geometries at 0.25 micron and above, substrate capacitance is usually the dominant effect. However, with geometries at 0.18 micron and below, the coupling capacitance between nets becomes significant, making crosstalk analysis increasingly important for accurate timing analysis. We show experimentally that the proposed codes allow reducing crosstalk delay by at least 14% based on available data.
EFFECT OF EQUAL AND MISMATCHED SIGNAL TRANSITION TIME ON POWER DISSIPATION IN...VLSICS Design
High density chips have introduced problems like crosstalk noise and power dissipation. The mismatching in transition time of the inputs occurs because different lengths of interconnects lead to different parasitic values. This paper presents the analysis of the effect of equal and unequal (mismatched) transition time of inputs on power dissipation in coupled interconnects. Further, the effect of signal skew on transition time is analysed. To demonstrate the effects, a model of two distributed RLC lines coupled capacitively and inductively is taken into consideration. Each interconnect line is 4mm long and terminated by capacitive load of 30fF. The analysis is carried out for simultaneously switching lines. The results are obtained through SPICE simulations and waveforms are generated.
The performance based analysis for typical Gaussian and Gaussian-Halo Doped Double Gate MOSFETs
in conjunction with Normal Doped DG MOSFETs, for which different parameters such as Oxide Thickness,
Ambient Temperature, Gate Material Work Function and Substrate Doping Concentration is varied. This
analysis has been carried out using a TCAD Lab simulation.. From the results obtained, it will be quite
clear that the sub-threshold leakage current of the Gaussian and Gaussian-Halo Doped Double Gate Metal
Oxide Semiconductor FET is relatively lesser. Furthermore the results have been plotted with different
Drain voltage values to enhance the understanding of the physics behind various Doping Profiles in
Double Gate MOSFET. Finally the results has been obtained, analysed and compared. The Possession of
higher Drain current Performance is very acceptable through the rigorous analysis using a TCAD Lab.
Performance Analysis of Double Hetero-gate Tunnel Field Effect TransistorIDES Editor
The document presents a double gate tunnel field effect transistor (TFET) with a hetero gate dielectric and low band gap material. Simulation results show the proposed device has higher on current, lower ambipolar current, and steeper subthreshold slope compared to a conventional silicon double gate TFET. Scaling the device provides better performance with negligible threshold voltage roll-off and reduced Miller capacitance. The hetero gate dielectric and low band gap material allow for improved tunneling probability and sharp subthreshold swing, making the device promising for low power applications.
Review of Fin FET Technology and Circuit Design Challengesrbl87
1. FinFET technology uses a fin-like gate structure to improve gate control and reduce leakage compared to planar CMOS. It allows continued transistor scaling beyond limits of planar devices.
2. There are manufacturing challenges for FinFETs including fin patterning and variability, doping, stress application, and parasitic capacitance. Circuit design challenges include adapting SRAM cells and EDA tools to the 3D FinFET structure.
3. FinFETs are now used for high performance logic but new materials and design approaches are still being explored to further improve FinFET technology and address remaining challenges in manufacturing and circuit design.
Multiple gate field effect transistors foreSAT Journals
This document provides a review of multiple gate field-effect transistors (MuGFETs), also known as FinFETs, as promising candidates to enable continued CMOS scaling. It discusses the motivation for multigate transistors due to short channel effects. It then summarizes the evolution of FinFET technologies, including variants like omega-gate and pi-gate FinFETs. Fabrication techniques like resist-defined fin and spacer-defined fin patterning are briefly outlined. Performance metrics like mobility, saturation velocity, transconductance and voltage gain are compared between FinFETs and planar MOSFETs based on measurements. FinFETs show lower resistance but higher voltage gain due to lower output conductance.
A Survey on Architectural Modifications for Improving Performances of Devices...IRJET Journal
This document summarizes research on improving the performance of FinFET devices through architectural modifications. FinFETs are promising replacements for bulk CMOS beyond the 22nm node due to their ability to better control short channel effects. Various techniques are discussed to enhance FinFET performance in terms of power, speed, and area. These include optimizing the fin geometry, gate work functions, strain engineering, and reducing parasitic capacitance. FinFETs also show improvements in noise reduction, scalability, and applications such as SRAM cells compared to planar CMOS devices. Overall, the document reviews how FinFET design modifications can help address challenges in continued device scaling for low power applications.
Electrical characterization of si nanowire GAA-TFET based on dimensions downs...IJECEIAES
This research paper explains the effect of the dimensions of Gate-all-around Si nanowire tunneling field effect transistor (GAA Si-NW TFET) on ON/OFF current ratio, drain induces barrier lowering (DIBL), sub-threshold swing (SS), and threshold voltage (V T ). These parameters are critical factors of the characteristics of tunnel field effect transistors. The Silvaco TCAD has been used to study the electrical characteristics of Si-NW TFET. Output (gate voltage-drain current) characteristics with channel dimensions were simulated. Results show that 50nm long nanowires with 9nm-18nm diameter and 3nm oxide thickness tend to have the best nanowire tunnel field effect transistor (Si-NW TFET) characteristics.
This document discusses FinFET technology. It begins with an introduction to FinFETs, explaining that they are a type of double-gate CMOS that offers advantages over traditional CMOS for scaling to short gate lengths. It then discusses why FinFET technology is needed as traditional CMOS scaling faces challenges from subthreshold and gate leakage. It provides details on double-gate FET structure and operation, including how it controls short-channel effects better than single-gate FETs. It also covers FinFET features, applications, challenges and concludes that FinFETs can help continue CMOS scaling if key issues like fin patterning and gate work functions are addressed.
This document summarizes the performance enhancement and characterization of a junctionless vertical slit field effect transistor (JLVeSFET). Key findings from simulations include:
1) The JLVeSFET shows an optimized subthreshold slope of 65mV/decade and OFF current of ~10-18A/μm for a 50nm radius device with a high-k dielectric.
2) Using a high-k dielectric (Si3N4) instead of SiO2 increases the Ion/Ioff ratio to ~1011 and reduces the subthreshold slope to 63mV/decade.
3) Increasing the gate doping concentration reduces the subthreshold slope slightly while increasing the Ion/
Structural and Electrical Analysis of Various MOSFET DesignsIJERA Editor
Invention of Transistor is the foundation of electronics industry. Metal Oxide Semiconductor Field Effect Transistor (MOSFET) has been the key to the development of nano electronics technology. This paper offers a brief review of some of the most popular MOSFET structure designs. The scaling down of planar bulk MOSFET proposed by the Moore’s Law has been saturated due to short channel effects and DIBL. Due to this alternative approaches has been considered to overcome the problems at lower node technology. SOI and FinFET technologies are promising candidates in this area.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document is a project report submitted for the degree of Master of Technology in Electronics and Communication Engineering. It discusses the design of FinFET-based nano-electronic circuits. Specifically, it analyzes different types of FinFET devices including shorted-gate, independent-gate, and asymmetric gate FinFETs. It also compares different FinFET-based standard cell designs including inverters and NAND2 gates using these different FinFET configurations in terms of area, delay, and leakage. Simulation results showing the output of a FinFET inverter are also presented. The document provides an overview of FinFET technology and circuits from the device to the circuit level.
Segmentation of Overlapped and Touching Human Chromosome imagesIOSR Journals
This document describes the design and analysis of a 4-bit Johnson counter using 16nm FinFET technology. It first discusses the advantages of FinFET over conventional CMOS for reducing short channel effects at small scales. It then presents the structure and manufacturing process of FinFET. A single-edge triggered D flip-flop using 9 FinFET transistors is proposed for use in the Johnson counter. The 4-bit Johnson counter is implemented by connecting 4 of these D flip-flops in a ring configuration. Simulation results show the waveforms of the D flip-flop and Johnson counter operating at 500MHz with 0.85V power supply. Compared to a conventional flip-flop-based counter, the proposed FinFET Johnson
This document describes the design and analysis of a 4-bit Johnson counter using 16nm FinFET technology. FinFETs help address short channel effects in smaller transistors and reduce power consumption compared to conventional CMOS. The document first discusses the FinFET structure and manufacturing process. It then presents the design of a low-power single edge-triggered D flip-flop using FinFETs. A 4-bit Johnson counter is implemented using four of these D flip-flops in a ring configuration. Simulation results show the FinFET D flip-flop consumes less power and the Johnson counter has lower power and area compared to designs using traditional flip-flops.
HIGH FIN WIDTH MOSFET USING GAA STRUCTUREVLSICS Design
This paper describes the design and optimization of gate-all-around (GAA) MOSFETs structures. The optimum value of Fin width and Fin height are investigated for superior subthreshold behavior. Also the performance of Fin shaped GAA with gate oxide HfO2 are simulated and compared with conventional gate oxide SiO2 for the same structure. As a result, it was observed that the GAA with high K dielectric gate oxide has more possibility to optimize the Fin width with improved performance. All the simulations are performed on 3-D TCAD device simulator.
This document analyzes and compares the performance of CMOS and FinFET logic technologies. It discusses key parameters for both technologies including gate area, gate capacitance, channel length, delay, subthreshold leakage current, and power dissipation. CMOS has advantages of low power consumption but suffers from short channel lengths. FinFET addresses this issue with a longer channel gate but higher power. The document provides equations to calculate parameters like power dissipation, delay dependence on input rise/fall time, impact of loading capacitance on gate delay, subthreshold leakage current, and threshold voltage for both CMOS and FinFET technologies.
FinFET technology uses a fin-like gate structure rather than a planar structure to help enable continued transistor scaling. FinFETs have a thin vertical "fin" structure rather than a flat design. This allows for better control of the channel and helps address issues like short channel effects. FinFETs can be fabricated using either a gate-first or gate-last process and involve patterning thin fins on a silicon-on-insulator wafer and then adding gate material. FinFETs offer benefits like reduced leakage currents and separate control of threshold voltages.
Dual Metal Gate and Conventional MOSFET at Sub nm for Analog ApplicationVLSICS Design
This document summarizes a study comparing a conventional MOSFET and dual metal gate (DMG) MOSFET at the 30nm technology node. Simulations were performed using Silvaco TCAD tools. Key results include:
1) The DMG MOSFET has a lower subthreshold slope and significantly lower gate leakage current compared to the conventional MOSFET.
2) Mobility and transconductance are higher in the DMG MOSFET, indicating better performance for analog applications that require high gain.
3) The DMG MOSFET has a higher intrinsic delay, making it more suitable for applications operated at lower voltages such as filters and sample-and-hold circuits, where gate
Performance analysis of ultrathin junctionless double gate vertical MOSFETsjournalBEEI
This document summarizes a study that analyzes the performance of ultrathin junctionless double gate vertical MOSFETs (JLDGVM) and compares them to conventional junctioned double gate vertical MOSFETs (JDGVM) through process and device simulation. The simulation results show that the drain current (ID) of n-type and p-type JLDGVM is enhanced by 57% and 60% respectively compared to JDGVM. Additionally, JLDGVM exhibit a larger ION/IOFF ratio and smaller subthreshold slope, implying better power consumption and faster switching capability than JDGVM. The junctionless configuration eliminates challenges associated with forming ultra-shallow junctions between the source/
Design & Performance Analysis of DG-MOSFET for Reduction of Short Channel Eff...IJERA Editor
An aggressive scaling of conventional MOSFETs channel length reduces below 100nm and gate oxide thickness below 3nm to improved performance and packaging density. Due to this scaling short channel effect (SCEs) like threshold voltage, Subthreshold slope, ON current and OFF current plays a major role in determining the performance of scaled devices. The double gate (DG) MOSFETS are electro-statically superior to a single gate (SG) MOSFET and allows for additional gate length scaling. Simulation work on both devices has been carried out and presented in paper. The comparative study had been carried out for threshold voltage (VT), Subthreshold slope (Sub VT), ION and IOFF Current. It is observed that DG MOSFET provide good control on leakage current over conventional Bulk (Single Gate) MOSFET. The VT (Threshold Voltage) is 2.7 times greater than & ION of DG MOSFET is 2.2 times smaller than the conventional Bulk (Single Gate) MOSFET.
FETs as a Congruous Hardware in Embedded Technology and SensorsCSCJournals
This document discusses different types of field effect transistors (FETs) that can be used in embedded technology and sensors. It classifies FETs based on the number of gates (single gate, double gate, tri gate, gate all around), arrangement (planar, non-planar), and composition materials (silicon, germanium, gallium arsenide, indium gallium arsenide, graphene). Multi-gate FETs like tri-gate and gate-all-around FETs are presented as promising technologies for future embedded processors that can support advanced machine learning algorithms through higher performance. The ideal FET technology depends on factors like material availability, switching speed, power dissipation, and scaling
Impact of parameter variations and optimization on dg pnin tunnel fetVLSICS Design
The downscaling of conventional MOSFETs has come to its fundamental limits. TFETs are very attractive
devices for low power applications because of their low off-current and potential for smaller sub threshold
slope. In this paper, the impact of various parameter variations on the performance of a DG-PNIN Tunnel
field effect transistor is investigated. In this work, variations in gate oxide material, source doping, channel
doping, drain doping, pocket doping and body thickness are studied and all these parameters are optimized
as performance boosters to give better current characteristics parameters. After optimization with all these
performance boosters, the device has shown improved performance with increased on-current and reduced
threshold voltage and the Ion/Ioff ratio is > 106.
Relevance of Grooved NMOSFETS in Ultra Deep Submicron Region in Low Power App...VLSICS Design
To manage the increasing static leakage in low power applications, solutions for leakage reduction are sought at the device design and process technology levels. In this paper, 90nm, 70nm and 50 nm groovedgate nMOS devices are simulated using Silvaco device simulator. By changing the corner angle and adjusting few structural parameters, static leakage reduction is achieved in grooved nMOSFETS in ultralow power applications. The simulation results show that leakage contributing currents like the subthreshold current, punchthrough current and tunneling leakage current are reduced. The oxide thickness can be increased without increase in the gate induced drain leakage current, and ON-OFF current ratio is improved and maintained constant even in the deep submicron region. This study can be helpful for low power applications as the static leakage is reduced drastically, as well as be applicable to high speed devices as the ON current is maintained at a constant value. The results are compared with those of corresponding conventional planar devices to bring out the achievements of this work.
Batteries -Introduction – Types of Batteries – discharging and charging of battery - characteristics of battery –battery rating- various tests on battery- – Primary battery: silver button cell- Secondary battery :Ni-Cd battery-modern battery: lithium ion battery-maintenance of batteries-choices of batteries for electric vehicle applications.
Fuel Cells: Introduction- importance and classification of fuel cells - description, principle, components, applications of fuel cells: H2-O2 fuel cell, alkaline fuel cell, molten carbonate fuel cell and direct methanol fuel cells.
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Review of Fin FET Technology and Circuit Design Challengesrbl87
1. FinFET technology uses a fin-like gate structure to improve gate control and reduce leakage compared to planar CMOS. It allows continued transistor scaling beyond limits of planar devices.
2. There are manufacturing challenges for FinFETs including fin patterning and variability, doping, stress application, and parasitic capacitance. Circuit design challenges include adapting SRAM cells and EDA tools to the 3D FinFET structure.
3. FinFETs are now used for high performance logic but new materials and design approaches are still being explored to further improve FinFET technology and address remaining challenges in manufacturing and circuit design.
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This document provides a review of multiple gate field-effect transistors (MuGFETs), also known as FinFETs, as promising candidates to enable continued CMOS scaling. It discusses the motivation for multigate transistors due to short channel effects. It then summarizes the evolution of FinFET technologies, including variants like omega-gate and pi-gate FinFETs. Fabrication techniques like resist-defined fin and spacer-defined fin patterning are briefly outlined. Performance metrics like mobility, saturation velocity, transconductance and voltage gain are compared between FinFETs and planar MOSFETs based on measurements. FinFETs show lower resistance but higher voltage gain due to lower output conductance.
A Survey on Architectural Modifications for Improving Performances of Devices...IRJET Journal
This document summarizes research on improving the performance of FinFET devices through architectural modifications. FinFETs are promising replacements for bulk CMOS beyond the 22nm node due to their ability to better control short channel effects. Various techniques are discussed to enhance FinFET performance in terms of power, speed, and area. These include optimizing the fin geometry, gate work functions, strain engineering, and reducing parasitic capacitance. FinFETs also show improvements in noise reduction, scalability, and applications such as SRAM cells compared to planar CMOS devices. Overall, the document reviews how FinFET design modifications can help address challenges in continued device scaling for low power applications.
Electrical characterization of si nanowire GAA-TFET based on dimensions downs...IJECEIAES
This research paper explains the effect of the dimensions of Gate-all-around Si nanowire tunneling field effect transistor (GAA Si-NW TFET) on ON/OFF current ratio, drain induces barrier lowering (DIBL), sub-threshold swing (SS), and threshold voltage (V T ). These parameters are critical factors of the characteristics of tunnel field effect transistors. The Silvaco TCAD has been used to study the electrical characteristics of Si-NW TFET. Output (gate voltage-drain current) characteristics with channel dimensions were simulated. Results show that 50nm long nanowires with 9nm-18nm diameter and 3nm oxide thickness tend to have the best nanowire tunnel field effect transistor (Si-NW TFET) characteristics.
This document discusses FinFET technology. It begins with an introduction to FinFETs, explaining that they are a type of double-gate CMOS that offers advantages over traditional CMOS for scaling to short gate lengths. It then discusses why FinFET technology is needed as traditional CMOS scaling faces challenges from subthreshold and gate leakage. It provides details on double-gate FET structure and operation, including how it controls short-channel effects better than single-gate FETs. It also covers FinFET features, applications, challenges and concludes that FinFETs can help continue CMOS scaling if key issues like fin patterning and gate work functions are addressed.
This document summarizes the performance enhancement and characterization of a junctionless vertical slit field effect transistor (JLVeSFET). Key findings from simulations include:
1) The JLVeSFET shows an optimized subthreshold slope of 65mV/decade and OFF current of ~10-18A/μm for a 50nm radius device with a high-k dielectric.
2) Using a high-k dielectric (Si3N4) instead of SiO2 increases the Ion/Ioff ratio to ~1011 and reduces the subthreshold slope to 63mV/decade.
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Structural and Electrical Analysis of Various MOSFET DesignsIJERA Editor
Invention of Transistor is the foundation of electronics industry. Metal Oxide Semiconductor Field Effect Transistor (MOSFET) has been the key to the development of nano electronics technology. This paper offers a brief review of some of the most popular MOSFET structure designs. The scaling down of planar bulk MOSFET proposed by the Moore’s Law has been saturated due to short channel effects and DIBL. Due to this alternative approaches has been considered to overcome the problems at lower node technology. SOI and FinFET technologies are promising candidates in this area.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document is a project report submitted for the degree of Master of Technology in Electronics and Communication Engineering. It discusses the design of FinFET-based nano-electronic circuits. Specifically, it analyzes different types of FinFET devices including shorted-gate, independent-gate, and asymmetric gate FinFETs. It also compares different FinFET-based standard cell designs including inverters and NAND2 gates using these different FinFET configurations in terms of area, delay, and leakage. Simulation results showing the output of a FinFET inverter are also presented. The document provides an overview of FinFET technology and circuits from the device to the circuit level.
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This document describes the design and analysis of a 4-bit Johnson counter using 16nm FinFET technology. It first discusses the advantages of FinFET over conventional CMOS for reducing short channel effects at small scales. It then presents the structure and manufacturing process of FinFET. A single-edge triggered D flip-flop using 9 FinFET transistors is proposed for use in the Johnson counter. The 4-bit Johnson counter is implemented by connecting 4 of these D flip-flops in a ring configuration. Simulation results show the waveforms of the D flip-flop and Johnson counter operating at 500MHz with 0.85V power supply. Compared to a conventional flip-flop-based counter, the proposed FinFET Johnson
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HIGH FIN WIDTH MOSFET USING GAA STRUCTUREVLSICS Design
This paper describes the design and optimization of gate-all-around (GAA) MOSFETs structures. The optimum value of Fin width and Fin height are investigated for superior subthreshold behavior. Also the performance of Fin shaped GAA with gate oxide HfO2 are simulated and compared with conventional gate oxide SiO2 for the same structure. As a result, it was observed that the GAA with high K dielectric gate oxide has more possibility to optimize the Fin width with improved performance. All the simulations are performed on 3-D TCAD device simulator.
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Physical Scaling Limits of FinFET Structure: A Simulation Study
1. International Journal of VLSI design & Communication Systems (VLSICS) Vol.2, No.1, March 2011
DOI : 10.5121/vlsic.2011.2103 26
Physical Scaling Limits of FinFET
Structure: A Simulation Study
Gaurav Saini1
, Ashwani K Rana2
Department of Electronics and Communication Engineering,
National Institute of Technology Hamirpur, Hamirpur, India
1
gaurav.nitham@gmail.com, 2
ashwani_paper@yahoo.com
Abstract
In this work an attempt has been made to analyze the scaling limits of Double Gate (DG) underlap and
Triple Gate (TG) overlap FinFET structure using 2D and 3D computer simulations respectively. To
analyze the scaling limits of FinFET structure, simulations are performed using three variables: fin-
thickness, fin-height and gate-length. From 2D simulation of DG FinFET, it is found that the gate-length
(L) and fin-thickness (Tfin) ratio plays a key role while deciding the performance of the device. Drain
Induced Barrier Lowering (DIBL) and Subthreshold Swing (SS) increase abruptly when (L/Tfin) ratio goes
below 1.5. So, there will be a trade-off in between SCEs and on- current of the device since on-off current
ratio is found to be high at small dimensions. From 3D simulation study on TG FinFET, It is found that
both fin-thickness (Tfin) and fin-height (Hfin) can control the SCEs. However, Tfin is found to be more
dominant parameter than Hfin while deciding the SCEs. DIBL and SS increase as (Leff/Tfin) ratio
decreases. The (Leff/Tfin) ratio can be reduced below 1.5 unlike DG FinFET for the same SCEs. However,
as this ratio approaches to 1, the SCEs can go beyond acceptable limits for TG FinFET structure. The
relative ratio of Hfin and Tfin should be maximum at a given Tfin and Leff to get maximum on-current per
unit width. However, increasing Hfin degrades the fin stability and degrades SCEs.
Keywords
Double Gate, Triple Gate, Underlap, Overlap, FinFET, High performance (HP), ITRS
1.Introduction
As technologies are scaled down in deep sub-half micron regime, the conventional bulk
MOSFET faces several challenges like higher DIBL, poor subthreshold swing collectively
known as SCEs [1]. Moreover, the gate oxide thickness has been reached to its physical limit
with the scaling i.e. below 1nm [2] and increasing gate leakage current is one of the most
challenging tasks for future scaling. It seems impossible to further scale down the gate oxide
beyond the inter-atomic distance. Future transistor scaling into the 21st
century requires new
solutions such as high-k gated dielectric materials and shallow, ultra low resistivity junctions
need to be developed [3]. To sustain scaling for the next decade, non-conventional solutions are
essentially required. Fully depleted Silicon-On-Insulator MOSFETs have received considerable
attention in recent years because of their various advantages such as improved isolation, reduced
subthreshold slope and parasitic capacitances and increased drive current. Today, SOI CMOS
has entered the mainstream technology due to their improved performance and the availability
of low cost SOI wafers. However, for the present generation FDSOI MOSFETs, the problems of
increased SCE, poor carrier mobility due to high channel doping and high gate leakage current
remain [4]. To overcome these limitations, several innovative multiple gates SOI structures such
as Double Gate (DG) MOSFET [5], fully depleted lean channel transistor (DELTA) [6] FinFET
[7-10], “Gate All Around” (GAA) MOSFET [11] and Pi-gate MOSFET [12] have been
2. International Journal of VLSI design & Communication Systems (VLSICS) Vol.2, No.1, March 2011
27
proposed by various researchers. It is expected that sustained scaling during the next decade will
see the evolution from the single gate (SG) conventional device to the multiple gate MOSFETs
(MuGFETs) [4]. Double gate FinFET is a promising candidate because of its quasiplanar
structure [8], excellent roll-off characteristics, drive current and it is close to its root, the
conventional MOSFET in terms of layout and fabrication [7, 8]. FinFET structure shows less
short channel effects than bulk MOSFET because of its self-aligned double gate [13] structure
and hence good electrostatic integrity. FinFETs have been demonstrated with both overlap and
underlap regions structures [14, 15]. FinFETs with graded or abrupt gate overlaps gives a higher
Ioff as the technologies are scaled down in deep sub-half micron regime [16], because of this, the
underlap structure with optimized doping profile in the underlap regions received a considerable
attention in the recent years [16, 17, 18]. The rest of the paper is organized as follows - In
section-2, device structure under investigation is presented, and section-3 describes the results
followed by conclusion in section-4.
2.Device Structure
Fig. 1 shows the DG FinFET structure realized using Setaurus TCAD tool suite [19]. Table I
shows the critical device parameters used to fabricate DG underlap FinFET structure given by
ITRS [2] for high performance multigate devices for the year of 2015. Based on this
specification DG FinFET underlap structure are fabricated and a comparison has been made to
analyze the scaling limits. Spacer underlap length (LUN) and source/drain exertion regions (Lext)
are kept at 10nm each in order to obtain a good On-off current ratio. Gaussian doping profile is
used in underlap regions.
3. International Journal of VLSI design & Communication Systems (VLSICS) Vol.2, No.1, March 2011
28
The Gaussian profile is selected in order to obtain a fall in doping concentration from 1020
cm-3
at the source/drain to 1016
cm-3
at the gate edges. The doping density of source, drain and
source/drain extensions are kept at 1020
cm-3
while channel is doped with a doping concentration
of 1015
cm-3
in order to achieve high mobility in the channel [20]. Workfuction of gate material
is adjusted to 4.51 eV in order to analyze the effects of gate dielectric constant variation. Table
II shows the critical device parameters used to fabricate TG overlap FinFET structure. Some
parameters follows the ITRS specification and some are user define. The Gaussian profile was
selected for doping in source, drain and overlap regions. The simulations are performed using
the Sentaurus design suite [19] with the drift-diffusion mobility, density-gradient quantum
correction modes being turned on for 2D. Hydrodynamic model is used in addition to drift-
diffusion mobility and density-gradient quantum correction modes for 3D.
Table 2
Device Parameters Used For TG FinFET
Device Parameters Values
Lg: Physical Gate-length 47 nm
Leff: Effective Gate-length 37 nm
Source and Drain overlaps 5 nm each
EOT: equivalent oxide thickness 1.5 nm
Vdd: Power supply voltage 1V
Lateral steepness of profile 3.2 nm/decade
Gate Workfunction 4.46 eV
Tfin 5-30 nm
Hfin 5-30 nm
3.Results and Discussion
3.1 Effects of gate-length variation on DG FinFET structure
Fig. 3 depicts threshold voltage variation with the gate-length. DG underlap FinFET shows a
well known effect “Threshold voltage roll-off”. The distance between drain and source reduces
with the gate-length and hence the channel potential is now more pronounced to the drain
electric field. So, the gate potential required to invert the channel is reduced because of the drain
electric field encroachment on the channel region increases with decreased gate-length.
4. International Journal of VLSI design & Communication Systems (VLSICS) Vol.2, No.1, March 2011
29
Fig. 2 Threshold voltage variation with gate-length
Fig. 3 Short Channel Effects variation with gate-length
Fig.3 depicts Short Channel Effects (SCEs) variation with the gate-length. DIBL increases very
sharply with decreased gate-length. The drain electric field encroachment on channel region
increases at shorter gate-lengths. Subthreshold swing also increases with decreased gate-length.
The gate now has less control over channel in subthreshold region because of the channel
barrier potential is now controlled by the drain potential also.
3.2 Effects of fin-thickness variation on DG FinFET structure
Fig. 4 shows the threshold voltage variation with the fin-thickness. Threshold voltage reduces
with increased fin-thickness. At shorter channel lengths, the surface potential depends not only
on capacitive coupling between the gate and the channel region but also on the capacitance of
source/fin and drain/fin junction. As the fin-thickness increases, the width of the source/fin and
drain/fin depletion region increases, which decreases the source/fin and drain/fin junction
capacitances, as a result the gate to surface potential coupling increases [24] and hence the
threshold voltage decreases with the increased film thickness.
Fig.5 shows Short Channel Effects (SCEs) variation with fin-thickness. Fin-thickness plays a
very important role while deciding SCEs. DIBL increases with increased fin-thickness. Drain
electric field lowers the barrier of channel in case of thick silicon film devices because of
reduced source/fin and drain/fin junction capacitances. Subthreshold swing also increases with
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
0 10 20 30
Vt(Volts)
Gate Length (nm)
0
20
40
60
80
100
0 5 10 15 20 25
DIBLandSS
Gate Length (nm)
DIBL(mV/V)
SS(mV/dec)
5. International Journal of VLSI design & Communication Systems (VLSICS) Vol.2, No.1, March 2011
30
fin-thickness. The reason behind this is the gate control over channel region degrades with
increased channel volume at constant drain and source proximity.
Fig. 4 Threshold voltage variation with fin-thickness
Fig. 5 Short Channel Effects variation with fin-thickness
3.3 Scaling limits of DG FinFET structure
Fig. 6 shows the effect of the ratio of gate-length (L) and fin-thickness (Tfin) on DIBL. This ratio
limits the scaling of DG FinFET structure. DIBL and subthreshold swing (SS) increases
abruptly when the L/Tfin ratio fall below1.5. This ratio is a most important factor which decides
the short channel effects. For DG FinFET structure fin-thickness could be a dominating factor
which decides the scaling capabilities.
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
0 5 10 15 20 25
Vt(Volts)
Fin Thickness (nm)
0
20
40
60
80
100
120
0 5 10 15 20 25
DIBLandSS
Fin Thickness (nm)
DIBL(mV/V)
SS(mV/dec)
6. International Journal of VLSI design & Communication Systems (VLSICS) Vol.2, No.1, March 2011
31
Fig. 6 Short Channel Effects variation with (L/Tfin) ratio
3.4 Effects of fin-thickness variation on TG FinFET structure
Fig. 7 depicts the threshold voltage variation with the fin-thickness. Threshold voltage reduces
with fin-thickness. The drain electric field lowers the channel barrier as we increases fin-
thickness because the channel area under the buried oxide (BOX) increases and hence drain
electric field induce more inversion charge at the bottom of silicon fin. There is a sharp rise in
the threshold voltage from 10nm to 5nm fin-thickness. It may be due to quantum mechanical
effects because below 10nm quantum effects dominates and cannot be neglected [25].
Fig. 7 Threshold voltage variation with the fin-thickness at 30nm of Hfin
Fig. 8 Short Channel Effects variation with fin-thickness at 30nm of Hfin
0
0.05
0.1
0.15
0.2
0.25
0.3
5 10 15 20 25 30 35
Vt(Volts)
Tfin (nm)
0
20
40
60
80
0 10 20 30 40
DIBLandSS
Tfin (nm)
DIBL(mV/V)
SS(mV/dec)
7. International Journal of VLSI design & Communication Systems (VLSICS) Vol.2, No.1, March 2011
32
Fig. 8 shows SCEs variation with the fin-thickness. DIBL increases with fin-thickness. The
drain electric field lowers the channel barrier as we increases fin-thickness because the channel
area under the BOX increases and hence drain electric field coupling with the channel increases.
Subthreshold swing also increases with fin-thickness. The reason is same as explained above.
The major portion of subthreshold current flows through the bottom layer of silicon fin because
of DIBL.
3.5 Effects of fin-heights variation on TG FinFET structure
Fig.9 depicts the threshold voltage variation with the fin-height. Threshold voltage reduces with
fin-height. At shorter channel lengths, the surface potential depends not only on capacitive
coupling between the gate and the channel region but also on the capacitance of source/fin and
drain/fin junction. As the fin-height increases, the width of the source/fin and drain/fin depletion
region increases, which decreases the source/fin and drain/fin junction capacitances, as a result
the gate to surface potential coupling increases and hence the threshold voltage decreases with
increased fin- height.
Fig. 9 Threshold voltage variation with the fin-height at 30nm of Tfin
Fig. 10 Short Channel Effects variation with fin-height at 30nm of Tfin
Fig. 10 shows SCEs variation with the fin-height. DIBL increases with the fin-height. The drain
electric field lowers the channel barrier as we increases fin-height. Subthreshold swing also
increases with fin-height. Gate loses its control over the channel with increased fin-height.
0
0.05
0.1
0.15
0.2
0.25
0.3
5 10 15 20 25 30 35
Vt(Volts)
Hfin (nm)
0
10
20
30
40
50
60
70
80
0 10 20 30 40
DIBLandSS
Hfin (nm)
DIBL(mV/V)
SS(mV/dec)
8. International Journal of VLSI design & Communication Systems (VLSICS) Vol.2, No.1, March 2011
33
3.6 Scaling limits of TG FinFET structure
Fig. 11 shows the effects of the ratio of effective gate-length (Leff) and fin-thickness (Tfin) on
SCEs. DIBL and subthreshold swing (SS) increases as (Leff/Tfin) ratio decreases. This ratio can
be reduced to less than 1.5 unlike DG FinFET for the same SCEs. However, as this ratio
approaches to 1 value the SCEs can go beyond acceptable limits. So, the scaling capabilities of
TG FinFET structure is more than that of DG FinFET structure.
Fig. 12 shows the effects of the ratio of effective gate-length (Leff) and fin-height (Hfin) on SCEs.
DIBL and subthreshold swing (SS) increases as (Leff/Tfin) ratio decreases, however, the
increment is less than that with the ratio (Heff/Tfin). The reason behind this is that the fin-
thickness is more prone to the SCEs than the fin-height. Fin-height can be increased to achieve
higher on-current than that of fin-thickness with an acceptable value of SCEs.
Fig. 11 Effects of (Leff/Tfin) ratio variation on SCEs at 30nm of Hfin
Fig. 12 Effects of (Leff/Hfin) ratio variation on SCEs at 30nm of Tfin
4.Conclusions
In this work, the scaling capabilities of DG and TG FinFET devices are analyzed using 2D and
3D simulation respectively. The (Leff/Tfin) ratio limits the scaling capabilities FinFET structure.
This ratio is found to be less in case of TG FinFET structure for acceptable SCEs. Simulation
9. International Journal of VLSI design & Communication Systems (VLSICS) Vol.2, No.1, March 2011
34
results shows that TG FinFET structure is more scalable than that of DG FinFET structure. The
relative ratio of Hfin and Tfin should be maximum at a given Tfin and Leff to get maximum on-
current per unit width. However, increasing Hfin degrades the fin stability, increases the
difficulty of gate patterning and degrades SCEs. Carefully optimization of Tfin and Hfin is
essentially required to get a good performance for scaled FinFET structure at a given gate
length.
5.Acknowledgement
The authors would like to thank the Department of Electronics and Communication
Engineering, National Institute of Technology Hamirpur (HP), Ministry of Communication and
Information Technology (MCIT), Department of Science and Technology, Government of India
for providing the advanced simulation tools.
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