G. Dambrine

80 GHz field-effect transistors produced using high purity semiconducting single-walled carbon nanotubes

This paper presents the high frequency performance of single-walled carbon nanotube (SWNT) field-effect transistors, with channel consisting of dense networks of high purity semiconducting SWNTs. Using SWNT samples containing 99% pure semiconducting SWNTs, we achieved operating frequencies above 80 GHz. This record frequency does not require aligned SWNTs, thus demonstrating the remarkable potential of random networks of sorted SWNTs for high frequency electronics.

What are the limiting parameters of deep-submicron MOSFETs for high frequency applications?

Parameters limiting the improvement of high frequency characteristics for deep submicron MOSFETs with the downscaling process of the channel gate length are analyzed experimentally and analytically. It is demonstrated that for MOSFETs with optimized source, drain and gate access, the degradation of the maximum oscillation frequency is mainly related to the increase of the parasitic feedback gate-to-drain capacitance and output conductance with the physical channel length reduction. Optimization of these internal parameters is needed to further improve the high frequency performance of ultra deep submicron MOSFETs.

Gigahertz frequency flexible carbon nanotube transistors

We investigate the high frequency performances of flexible field-effect transistors based on carbon nanotubes. A large density of mostly aligned carbon nanotubes deposited on a flexible substrate by dielectrophoresis serves as the channel. The transistors display a constant transconductance up to at least 6GHz and a current gain cutoff frequency (fT) as high as 1GHz at VDS=−700mV. Bending tests show that the devices can withstand a high degree of flexion characterized by a constant transconductance for radius of curvature as small as 3.3mm.

Low Temperature Implementation of Dopant-Segregated Band-edge Metallic S/D junctions in Thin-Body SOI p-MOSFETs

This paper proposes the implementation of a dopant segregated band-edge silicide using implantation-to-silicide and low temperature activation (500degC). The integration of platinum silicide coupled to boron segregation demonstrates a 50% enhancement of the current drive over the dopant-free approach. RF characterization unveils a cut-off frequency fT of 180 GHz at Lg=30 nm without application of channel stressors.

Direct extraction of the series equivalent circuit parameters for the small-signal model of SOI MOSFETs

A new extraction scheme is proposed which allows to determine all the series equivalent circuit elements values from S-parameters measurements at a single bias point in saturation. Exploiting the specific shape of a set of impedance loci, the new scheme uses linear regression techniques to solve the extraction problem. The resulting algorithm is very simple and efficient when compared to optimizer-driven approaches.

An 8-GHz f/sub t/ carbon nanotube field-effect transistor for gigahertz range applications

In this letter, the authors report on the high-frequency (HF) performance of self-assembled carbon nanotube field-effect transistors. HF device structures including a large number of single-wall carbon nanotubes have been designed and optimized in order to establish a new state of the art. The device exhibits a current gain (|H21| 2) cutoff frequency (ft) of 8 GHz and a maximum stable gain value of 10 dB at 1 GHz, after de-embedding the access pads. Considering such results, nanotube-based circuits with gigahertz performance are now conceivable

Gigahertz characterization of a single carbon nanotube

Carbon nanotubes are intrinsically high impedance objects. The high frequency (HF) characterization of these nano-objects is crucial for applications such as interconnects in future integrated circuits, but still represents a daunting challenge. This letter presents HF characterization of an individual metallic single walled carbon nanotube up to 7 GHz. The equivalent circuit values are directly extracted from these HF measurements without numerical procedure, thus proving that the intrinsic transport parameters of a single carbon nanotube can be determined up to gigahertz frequencies.

High-Speed SiGe BiCMOS Technologies: 120-nm Status and End-of-Roadmap Challenges

This paper presents the status of high-speed SiGe BiCMOS technologies at STMicroelectronics. Process and electrical characteristics of two 120-nm platforms, qualified or under development, are presented together with results demonstrated on optical and millimeter-wave circuits. Advanced developments addressing end-of-roadmap BiCMOS are also presented and discussed

A new empirical nonlinear model for sub-250 nm channel MOSFET

An empirical nonlinear model for sub-250 nm channel length MOSFET is presented which is useful for large signal RF circuit simulation. Our model is made of both analytical drain current and gate charge formulations. The drain current expression is continuous and infinitely derivable, and charge conservation is taken into account, as the capacitances derive from a single charge expression. The models parameters are first extracted, prior the models implementation into a circuit simulator. It is validated through dc, ac, and RF large signal measurements compared to the simulation.

Active properties of carbon nanotube field-effect transistors deduced from S parameters measurements

AC performances of carbon nanotube field-effect transistors (CNT-FETs) are analyzed by means of scattering parameters measurements. The active ac properties of CNT-FETs are clearly demonstrated up to 80 MHz and indications of active behavior are obtained up to 1 GHz. From these measurements, a small signal equivalent circuit is proposed and validated up to 10 MHz. The extraction procedure and the determination of the intrinsic ac elements of CNT-FETs are pointed out