Overview of Carbon Nanotube Field-Effect Transistors (original) (raw)
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A Review Article on Carbon Nanotube Field Effect Transistors Technology
CSVTU Research Journal on Engineering and Technology
As Silicon industry is evolving it is scaling down day by day. With the reduced size of the transistor, the craving for high performance devices has also taken place. For MOSFET, with very small channel length size reduction is limited and below certain dimensions the device will undergo uncontrolled and unpredictable leakage current, parasitic capacitances and power dissipation issues. Hence, researchers have implemented a novel device to overcome the above-mentioned issues called as CNTFET (Carbon NanoTube Field Effect Transistor). CNTFET provides high carrier mobility, reduced delay and power consumption, better noise margin, suitable contact resistance and fast switching speed. In this review paper, different CNTFET structures and classifications, chiral vector and chirality have been discussed in detail.
Carbon Nanotubes Field Effect Transistor : A Review
2015
In this paper we have focused on the carbon nano tube field effect transistor technology. The advantages of CNTFET over MOS technology are also discussed. The structure and types of CNTFET are given in detail along with the variation of threshold voltage with respect to the alteration in CNT diameter. The characteristics curve between gate to source current and drain to source voltage is plotted. Various fixed and variable parameters of CNT are also focused.
CARBON NANOTUBE FIELD-EFFECT TRANSISTORS
International Journal of High Speed Electronics and Systems, 2006
This paper discusses the device physics of carbon nanotube field-effect transistors (CNTFETs). After reviewing the status of device technology, we use results of our numerical simulations to discuss the physics of CNTFETs emphasizing the similarities and differences with traditional FETs. The discussion shows that our understanding of CNTFET device physics has matured to the point where experiments can be explained and device designs optimized. The paper concludes with some thoughts on challenges and opportunities for CNTFET electronics.
Fabrication of Carbon Nanotube Field Effect Transistor
IETE Technical Review, 2011
Single wall carbon nanotubes (SWNTs) suspended in isopropyl alcohol have been placed between two electrodes by AC dielectrophoresis method. The number of SWNTs bridging the two electrodes is controlled by SWNT concentration of the suspension and deposition time. Through selectively burning off the metallic SWNTs by current induced oxidation, the back-gate carbon nanotube field effect transistors (CNTFETs) with a channel current on-off ratio of up to 7 · 10 5 have been successfully fabricated. The success rate of the CNTFETs in 20 samples is 60%. These results suggest that AC dielectrophoresis placement method is an efficient technique to fabricate CNTFETs with some flexibilities of controlling CNT reconnection, length and orientation.
Novel Structures for Carbon Nanotube Field Effect Transistors
International Journal of Modern Physics B, 2009
A carbon nanotube field effect transistor (CNTFET) has been studied based on the Schrödinger–Poisson formalism. To improve the saturation range in the output characteristics, new structures for CNTFETs are proposed. These structures are simulated and compared with the conventional structure. Simulations show that these structures have a wider output saturation range. With this, larger drain-source voltage (Vds) can be used, which results in higher output power. In the digital circuits, higher Vds increases noise immunity.
This paper discusses a comprehensive analytical study of electrical properties of sin-gle‐wall conventional carbon nanotube field‐effect transistor (CNTFET) devices of subthreshold swing (SS), transconductance (g m), and extension resistance. The analytical expressions for SS and g m have been derived based on channel modulated potential. In the study, it was observed that SS value of the CNTFET device is equal to 60 mV/decade, which is smaller than the conventional and double gate metal‐ oxide‐semiconductor field‐effect transistors. The subthreshold swing degrades at larger tube's diameter and gate‐source voltage due to increased source‐drain leakage current. Carbon nanotube field‐effect transistor devices achieve larger g m at large gate‐source voltage, which has a disadvantage of reducing the allowable voltage swing at the drain. The extension resistance of the device falls with diameter of the tube. The subthreshold swing (SS) is the important parameter to sustain the scaling of silicon transistor because leakage power is strongly influenced by SS of the device. Subthreshold swing value indicates the minimum gate‐source voltage (V gs) required to lower the subthreshold current by a factor of 10. Steep SS devices are of great interest due to demand of power and energy‐efficient digital circuits. As metal‐oxide‐semiconductor field‐effect transistors (MOSFETs) scaled below 45 nm, the subthreshold leakage current becomes more significant due to short‐channel effects (SCEs), parameter variations, 1-3 and strong coupling between temperature and subthreshold leakage current. 4,5 The fundamental thermodynamic limit on the minimum operational voltage and switching energy of the conventional FETs is ideally 60 mV/decade at room temperature, but in practice , the gate oxide screens the gate fields and the coupling between the gate and channel is not perfect, which causes SS to be larger than the ideal value. 6-10 The carbon nanotube FET (CNTFET) is a promising candidate for future electron devices, and rapid progress in this field has made it possible to fabricate CNTFET‐based integrated circuits. In facts, CNTFET is the substitute of silicon MOS due to excellent control of SCEs 11-13 as well as physical and electrical properties. 14,15 Although the SS of the CNTFET device has been reported theoretically by researchers, 16-18 this parameter has not been discussed in detail compared with the other parameters. In nanotube junctions, the parasitic resistance (R P) is given as the sum of contact resistance (R C) and the extension resistance (R ext). The R ext contributes more in the R P than in the R C. Lower R ext improves the intrinsic performance of the device. 19 In the literature, less attention has been given on the study of R ext compared with R C. 20 In this paper, we studied the SS and R ext of CNTFET after using our previously derived drain current equation. 15 The SS is close to 60 mV/decade at room temperature in CNTFET device. We have also observed that the SS of the CNTFET device is
A Study on Carbon Nano-Tube Field Effect Transistor (CNTFETs): A Promising Technology for future ICs
2020
Presently, the low power and high efficiency are imperishable problem in technological gadgets. With the emergence of technologies like 5G and others, it has become requisite to meet the challenge before peeved. In this paper we entrust FinFETs, and CNTFETs technologies which are found to be upbeat field of research. The paper presents the performance enhancements of CNTFETs at 14 nm node and discusses the important areas of their applications and future scope.
Simulations of Carbon Nanotube Field Effect Transistors
… Journal of Electronic Engineering Research, ISSN
As the scaling of Si MOSFET approaches towards its limiting value, new alternatives are coming up to overcome these limitations. In this paper first we have reviewed carbon nanotube field effect transistor (CNTFET) and types of CNTFET. We have then studied the effect of channel length and chirality on the drain current for planer CNTFET. The I d~Vd curves for planer CNTFETs having different channel lengths and diameters are plotted. For the same, I d~Vd curves for different applied gate voltages are also plotted. We have then discussed the effect of diameter on the characteristic curves for a cylindrical CNTFET. Finally a brief comparison between the performance of Si-MOSFET and CNTFET is given.
c World Scientic Publishing Company NOVEL STRUCTURES FOR CARBON NANOTUBE FIELD EFFECT TRANSISTORS
2007
A carbon nanotube eld eect transistor (CNTFET) has been studied based on the Schrodinger{Poisson formalism. To improve the saturation range in the output charac-teristics, new structures for CNTFETs are proposed. These structures are simulated and compared with the conventional structure. Simulations show that these structures have a wider output saturation range. With this, larger drain-source voltage (V ds) can be used, which results in higher output power. In the digital circuits, higher V ds increases noise immunity.
Massive manufacture and characterization of single-walled carbon nanotube field effect transistors
Microelectronic Engineering, 2010
A technology to address massive and batch fabrication of carbon nanotube field effect transistors (CNT-FET) based systems at wafer level is presented. In order to demonstrate the feasibility of the technology, we have designed, fabricated, tested and evaluated a CNT-FET based monitor chip. The monitor chip is composed of 16 different in design CNT-FET structures. In total, each monitor chip contains 5760 devices. Each wafer is composed of 24 monitor chips. Evaluation of the data obtained through automatic test procedures gives evidence of the fabrication of more than 10,000 functional CNT-FET on a 4 inch wafer. A yield of functional CNT-FET of 27% has been achieved for optimal designs.