Numerical Evaluation of the Effect of Geometric Tolerances on the High-Frequency Performance of Graphene Field-Effect Transistors

Abstract

The interest in graphene-based electronics is due to graphene’s great carrier mobility, atomic thickness, resistance to radiation, and tolerance to extreme temperatures. These characteristics enable the development of extremely miniaturized high-performing electronic devices for next-generation radiofrequency (RF) communication systems. The main building block of graphene-based electronics is the graphene-field effect transistor (GFET). An important issue hindering the diffusion of GFET-based circuits on a commercial level is the repeatability of the fabrication process, which affects the uncertainty of both the device geometry and the graphene quality. Concerning the GFET geometrical parameters, it is well known that the channel length is the main factor that determines the high-frequency limitations of a field-effect transistor, and is therefore the parameter that should be better controlled during the fabrication. Nevertheless, other parameters are affected by a fabrication-related tolerance; to understand to which extent an increase of the accuracy of the GFET layout patterning process steps can improve the performance uniformity, their impact on the GFET performance variability should be considered and compared to that of the channel length. In this work, we assess the impact of the fabrication-related tolerances of GFET-base amplifier geometrical parameters on the RF performance, in terms of the amplifier transit frequency and maximum oscillation frequency, by using a design-of-experiments approach.

Synergy of Electrostatic and Chemical Doping to Improve the Performance of Junctionless Carbon Nanotube Tunneling Field-Effect Transistors: Ultrascaling, Energy-Efficiency, and High Switching Performance

“…In the literature, the junctionless-carbon-nanotube-tunnel field-effect transistors (JL CNTTFETs) have shown promising subthreshold and switching performance [ 5 , 10 , 11 ] due to the amazing characteristics of carbon nanotube (CNT) as mature channel material, such as atomic structure, tunable band gap, high electrical conductivity, quasi-ballistic property, high Fermi velocity, and high sensitivity to its surrounded electrostatics (i.e., the electrostatic gating) [ 12 , 13 , 14 , 15 ]. However, as any electronic nanodevice, the ultrascaled JL CNTTFET suffers from some weaknesses, namely the low on-current and the issue of direct source-to-drain tunneling (DSDT), which is attributed to the low effective mass in the carbon nanotube [ 16 , 17 , 18 ].…”

Graphene Devices for Aerial Wireless Communications at THz

“…The high-frequency amplification performance of the same GFET of Figure 2 [6]. It is also important to notice that the high-frequency performance of GFETs is strongly impaired by the fluctuations of the design parameters related to the fabrication issues [46], [47]. GFETs can also be used to design RF phase shifters [8], used for instance to modulate the RF signal phase for the beamforming in phased array antennas, and ring oscillators [9], as local oscillator for the carrier signal generation…”

Assessing the Microfabrication-Related Variability of the Performance of CMUT Arrays

“…Though, this approach neglects the possibility that the simultaneous variation of two or more factors affects the observed output quantity differently than if the factors were varying individually. It is therefore more adequate to use a factorial approach to the design of experiments, which considers multiple cases of combined variations of factors, since this method allows the assessment of interactions between factors and a straightforward extraction of prediction models for the response variability [37]- [39].…”