Short-channel and high-mobility p- and n-type organic single-crystal transistors with air-gap structures

2012 ◽  
Vol 1402 ◽  
Author(s):  
M. Uno ◽  
T. Uemura ◽  
K. Miwa ◽  
A. Facchetti ◽  
J. Takeya

ABSTRACTIn an effort to realize high-speed organic logic components, p- and n-type single-crystal organic field-effect transistors (SC-OFETs) were fabricated using air-gap structures with channel lengths as short as several μm. High carrier mobility of about 10 cm2/Vs is demonstrated in rubrene SC-OFETs even with the short channel length of 6 μm, using Si-based microstructures. The contact resistance is estimated to be 450 Ohm cm, which is only 5% of the total channel resistance between source and drain electrodes. Performances of n-type air-gap devices based on PDIF-CN2 are also demonstrated exhibiting electron transport with the carrier mobility of about 2 cm2/Vs. Furthermore, micron-scale air-gap structures are fabricated using insulating materials on glass substrates to reduce parasitic gate capacitance. The cut-off frequency of this rubrene air-gap device is measured to be as high as 8 MHz with applied drain voltage VD of 15 V. These techniques are promising to be applicable to next-generation organic high-speed logic circuits.

2017 ◽  
Vol 2 (2) ◽  
pp. 15-19 ◽  
Author(s):  
Md. Saud Al Faisal ◽  
Md. Rokib Hasan ◽  
Marwan Hossain ◽  
Mohammad Saiful Islam

GaN-based double gate metal-oxide semiconductor field-effect transistors (DG-MOSFETs) in sub-10 nm regime have been designed for the next generation logic applications. To rigorously evaluate the device performance, non-equilibrium Green’s function formalism are performed using SILVACO ATLAS. The device is turn on at gate voltage, VGS =1 V while it is going to off at VGS = 0 V. The ON-state and OFF-state drain currents are found as 12 mA/μm and ~10-8 A/μm, respectively at the drain voltage, VDS = 0.75 V. The sub-threshold slope (SS) and drain induced barrier lowering (DIBL) are ~69 mV/decade and ~43 mV/V, which are very compatible with the CMOS technology. To improve the figure of merits of the proposed device, source to gate (S-G) and gate to drain (G-D) distances are varied which is mentioned as underlap. The lengths are maintained equal for both sides of the gate. The SS and DIBL are decreased with increasing the underlap length (LUN). Though the source to drain resistance is increased for enhancing the channel length, the underlap architectures exhibit better performance due to reduced capacitive coupling between the contacts (S-G and G-D) which minimize the short channel effects. Therefore, the proposed GaN-based DG-MOSFETs as one of the excellent promising candidates to substitute currently used MOSFETs for future high speed applications.


VLSI Design ◽  
2008 ◽  
Vol 2008 ◽  
pp. 1-5
Author(s):  
Sotoudeh Hamedi-Hagh ◽  
Ahmet Bindal

Vertical nanowire surrounding gate field effect transistors (SGFETs) provide full gate control over the channel to eliminate short-channel effects. This paper presents design and characterization of a differential pair amplifier using NMOS and PMOS SGFETs with a 10 nm channel length and a 2 nm channel radius. The amplifier dissipates 5 μW power and provides 5 THz bandwidth with a voltage gain of 16, a linear output voltage swing of 0.5 V, and a distortion better than 3% from a 1.8 V power supply and a 20 aF capacitive load. The 2nd- and 3rd-order harmonic distortions of the amplifier are −40 dBm and −52 dBm, respectively, and the 3rd-order intermodulation is −24 dBm for a two-tone input signal with 10 mV amplitude and 10 GHz frequency spacing. All these parameters indicate that vertical nanowire surrounding gate transistors are promising candidates for the next generation high-speed analog and VLSI technologies.


2017 ◽  
Vol 31 (01) ◽  
pp. 1650242 ◽  
Author(s):  
Behrooz Abdi Tahne ◽  
Ali Naderi

In this paper, a new structure, step–linear doping MOSCNT (SLD-MOSCNT), is proposed to improve the performance of basic MOSCNTs. The basic structure suffers from band to band tunneling (BTBT). We show that using SLD profile for source and drain regions increases the horizontal distance between valence and conduction bands at gate to source/drain junction which reduces BTBT probability. SLD performance is compared with other similar structures which have recently been proposed to reduce BTBT such as MOSCNT with lightly-doped drain and source (LDDS), and with double-light doping in source and drain regions (DLD). The obtained results using a nonequilibrium Green’s function (NEGF) method show that the SLD-MOSCNT has the lowest leakage current, power consumption and delay time, and the highest current ratio and voltage gain. The ambipolar conduction in the proposed structure is very low and can be neglected. In addition, these structures can improve short-channel effects. Also, the investigation of cutoff frequency of the different structures shows that the SLD has the highest cutoff frequency. Device performance has been investigated for gate length from 8 to 20 nm which demonstrates all discussions regarding the superiority of the proposed structure are also valid for different channel lengths. This improvement is more significant especially for channel length less than 12 nm. Therefore, the SLD can be considered as a candidate to be used in the applications with high speed and low power consumption.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Goutham Arutchelvan ◽  
Quentin Smets ◽  
Devin Verreck ◽  
Zubair Ahmed ◽  
Abhinav Gaur ◽  
...  

AbstractTwo-dimensional semiconducting materials are considered as ideal candidates for ultimate device scaling. However, a systematic study on the performance and variability impact of scaling the different device dimensions is still lacking. Here we investigate the scaling behavior across 1300 devices fabricated on large-area grown MoS2 material with channel length down to 30 nm, contact length down to 13 nm and capacitive effective oxide thickness (CET) down to 1.9 nm. These devices show best-in-class performance with transconductance of 185 μS/μm and a minimum subthreshold swing (SS) of 86 mV/dec. We find that scaling the top-contact length has no impact on the contact resistance and electrostatics of three monolayers MoS2 transistors, because edge injection is dominant. Further, we identify that SS degradation occurs at short channel length and can be mitigated by reducing the CET and lowering the Schottky barrier height. Finally, using a power performance area (PPA) analysis, we present a roadmap of material improvements to make 2D devices competitive with silicon gate-all-around devices.


1996 ◽  
Vol 428 ◽  
Author(s):  
Abhijit Phanse ◽  
Samar Saha

AbstractThis paper addresses hot-carrier related reliability issues in deep submicron silicon nMOSFET devices. In order to monitor the hot-carrier induced device degradation, the substrate current was measured for devices with varying channel lengths (20 um - 0.24 um) under various biasing conditions. Deep submicron devices experience velocity saturation of channel carriers due to extremely high lateral electric fields. To evaluate the effects of velocity saturation in the channel, the pinch-off length in the channel was extracted for all the devices of the target technology. It was observed that for very short channel devices, carriers in most of the channel experience velocity saturation and almost the entire channel gets pinched off. It is shown in this paper that for very short channel devices, the pinch-off length in the channel is limited by the effective channel length, and that velocity saturation effects are critical to the transport of channel carriers.


2014 ◽  
Vol 15 (11) ◽  
pp. 2696-2701 ◽  
Author(s):  
Yudai Yoshimura ◽  
Yasunori Takeda ◽  
Kenjiro Fukuda ◽  
Daisuke Kumaki ◽  
Shizuo Tokito

Author(s):  
Raj Kumar ◽  
Shashi Bala ◽  
Arvind Kumar

To have enhanced drive current and diminish short channel effects, planer MOS transistors have migrated from single-gate devices to three-dimensional multi-gate MOSFETs. The gate-all-around nanowire field-effect transistor (GAA NWFET) and nanotube or double gate-all-around field-effect transistors (DGGA-NTFET) have been proposed to deal with short channel effects and performance relates issues. Nanowire and nanotube-based field-effect transistors can be considered as leading candidates for nanoscale devices due to their superior electrostatic controllability, and ballistic transport properties. In this work, the performance of GAA NWFETs and DGAA-NT FETs will be analyzed and compared. III-V semiconductor materials as a channel will also be employed due to their high mobility over silicon. Performance analysis of junctionless nanowire and nanotube FETs will also be compared and presented.


1984 ◽  
Vol 33 ◽  
Author(s):  
Z. Yaniv ◽  
G. Hansell ◽  
M. Vijan ◽  
V. Cannella

ABSTRACTA new method of fabricating short channel α-Si TFTs has been developed. One-micrometer channel length α-Si thin-film field effect transistors have been fabricated and tested. Threshold voltages as low as 1.9V and field-effect mobilities as high as 1 cm 2/V-sec are reported. These devices were fabricated by techniques compatible with the production of large area liquid crystal displays.


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