L-band carbon nanotube transistor amplifier

IEEE Trans. Electron Devices

Haferlach

Pacheco‐Sanchez

et al. 2015

A compact large-signal model, called Compact Carbon Nanotube Model (CCAM), is presented that accurately describes the shape of DC and small-signal characteristics of fabricated carbon nano-tube FETs (CNTFETs). The new model consists of computationally efficient and smooth current and charge formulations. The model allows, for a given gate length, geometry scaling from single-finger single-tube to multifinger multitube transistors. Ambipolar transport, temperature dependence with self-heating, noise, and a simple trap model have also been included. The new model shows excellent agreement with the data from both the Boltzmann transport equation and measurements of Schottky-barrier CNTFETs and has been implemented in Verilog-A, making it widely available across circuit simulators. IndexTerms-Carbon nanotube field-effect transistor (CNTFET), compact transistor modeling, high-frequency circuit design.

Section: Resultsmentioning

confidence: 97%

Section: Methodsmentioning

confidence: 93%

See 1 more Smart Citation

A Semiphysical Large-Signal Compact Carbon Nanotube FET Model for Analog RF Applications

IEEE Trans. Electron Devices

Haferlach

Pacheco‐Sanchez

et al. 2015

“…The devices were fabricated with the process technology described in Refs. 9–11. To enable high frequency measurements the CNTFETs were embedded in RF pads, as it is seen in the left image of the abstract.…”

Section: Device Under Test (Dut)mentioning

confidence: 99%

Experimental characterization of temperature‐dependent electron transport in single‐wall multi‐tube carbon nanotube transistors

Sakalas

Claus

Physica Rapid Research Ltrs

et al. 2011

Current–voltage, radio‐frequency (RF) and noise characteristics of single‐wall multi‐tube carbon nanotube (CNT) transistors were measured at cryogenic temperatures. Compared to an ambient temperature (Ta) of 300 K, only a slight drain current increase at Ta = 77 K was observed. In addition, a weak dependence of the maximum value of the current gain cut‐off frequency (fT) on Ta was obtained, indicating that fT is rather limited by the device intrinsic quantum and extrinsic capacitances than by an improved mobility due to reduced optical phonon scattering at low Ta. A noise analysis of the devices at Ta = 10 K reveals that the noise factor (NF) improvement at very low temperatures is related to the reduced Nyquist noise of all resistive transistor noise contributors. Since the main noise source in CNTFETs is the shot noise, NF remains comparatively high even at Ta = 10 K. Photo of the CNTFET embedded in RF pads (left) and schematic layout of the CNTFET (right). (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

“…With the more recent realization of the issues faced by using graphene for transistor applications, carbon nanotube (CNT) field-effect transistors (FETs) are again within the research focus for analog high-frequency (HF) applications due to their unique intrinsic electrical properties and the recent advances in CNTFET technologies [1], [2] and related circuit design studies [3]- [5]. For a thorough comparison between graphene FETs and CNT-based 1D-electronics for HF applications, the interested reader is referred to [6], [7].…”

Section: Introductionmentioning

confidence: 99%

About the charge injection limitation in Schottky barrier CNTFETs

Claus

Mothes

2013 International Semiconductor Conference Dresden - Grenoble (ISCDG)

2013

The injection of charges into the channel of a carbon nanotube (CNT) field effect transistor (FET), and, hence, the overall device behavior are strongly affected by the interface between the CNT and the metall contacts and the tube portion underneath the metall contacts (contact region). The properties of the interface and the contact region depend on details of the fabrication process and the materials used. Thus, a detailed understanding of the related phenomena facilitates device and process optimization. A major issue in optimizing the interface and the contact region is the limitation of charge injection due to potential barriers in the contact region and clipping. The limitation along with the transport within the channel is studied by means of the Boltzmann-transport equation (BTE) in combination with a phenomenological contact model which also considers tunneling through near-contact potential barriers. The related results are discussed with respect to CNT-based 1D-electronics for high-frequency (HF) analog applications.