The influences of radiation effects on DC/RF performances of Lg=22 nm gate-all-around nanosheet field-effect transistor

In this paper, we carried out detailed TCAD simulations to investigate the radiation effects, e.g., total ionizing dose (TID) and single-event effects (SEEs), on direct current (DC) and radio frequency (RF) characteristics of the gate-all-around (GAA) nanosheet field-effect transistor (FET). The simulation model used is composed of 7-layer stacked GAA nanosheet FET with Lg=22 nm, which was implemented in this study. The open current and the drain-induced barrier lowering of the device are ~ 3mA/μm and 47mV/V, respectively. The results indicate that the TID have little influence on the DC and RF characteristics when the transistor is working in an open state. During the SEEs simulation, we considered three incident directions for the high energy particle, including the lateral direction of the channels, the vertical direction of the channels and the top of the channels. The influence of the particle injecting along the lateral and vertical directions of the channels shows stronger relation with the distance from the incident point compared to the influence of the particle from the top. Besides, the general influence of the particle injecting along the lateral directions of the channels is higher than the other two directions. The total injected charge of the particle injecting along the lateral direction, along the vertical direction and from the top are 3 fC, 1.4 fC and 2.1 fC, respectively. As compared to the FinFET, the GAA nanosheet has superior RF performances and less sensitivity to TID effect. This work can provide a guideline for the GAA nanosheet devices in aerospace and avionic RF applications.

Towards an integrated neonatal brain and cardiac examination capability at 7 T: electromagnetic field simulations and early phantom experiments using an 8-channel dipole array

Objective Neonatal brain and cardiac imaging would benefit from the increased signal-to-noise ratio levels at 7 T compared to lower field. Optimal performance might be achieved using purpose designed RF coil arrays. In this study, we introduce an 8-channel dipole array and investigate, using simulations, its RF performances for neonatal applications at 7 T. Methods The 8-channel dipole array was designed and evaluated for neonatal brain/cardiac configurations in terms of SAR efficiency (ratio between transmit-field and maximum specific-absorption-rate level) using adjusted dielectric properties for neonate. A birdcage coil operating in circularly polarized mode was simulated for comparison. Validation of the simulation model was performed on phantom for the coil array. Results The 8-channel dipole array demonstrated up to 46% higher SAR efficiency levels compared to the birdcage coil in neonatal configurations, as the specific-absorption-rate levels were alleviated. An averaged normalized root-mean-square-error of 6.7% was found between measured and simulated transmit field maps on phantom. Conclusion The 8-channel dipole array design integrated for neonatal brain and cardiac MR was successfully demonstrated, in simulation with coverage of the baby and increased SAR efficiency levels compared to the birdcage. We conclude that the 8Tx-dipole array promises safe operating procedures for MR imaging of neonatal brain and heart at 7 T.

Influence of Variation in Oxide layer Thickness on Analog and RF performances of SOI FinFET

In this paper, the influence of oxide (SiO2) layer thickness on the different figure of merits of a FinFET is analysed by varying the oxide layer thickness which is present between the gate and the Fin. Here, the overall thickness of the FinFET is taken to be 30nm, and the oxide (SiO2) layer thickness is changed from 0.8 nm to 3nm, and the analog, radio frequency parameters are determined for different structures. The performance parameters like drain current (ID), transconductance generation factor (TGF), transconductance (gm), output conductance (gds), parasitic capacitances like Cgs, Cgd, Cgg, cut-off frequency (fT), gain bandwidth product (GBW) and maximum frequency of oscillation (fmax) are calculated to learn the influence of variation in the FinFET oxide (SiO2) layer thickness. It is detected from the result and analysis that the drain current, output conductance, transconductance generation factor, transconductance and gain bandwidth product improve with decrement in oxide layer thickness. But as a tradeoff, the internal capacitances like Cgs, Cgd, Cgg, maximum frequency of oscillation and cut-off frequency degrade when there is a reduction in oxide (SiO2) layer thickness.

Work function variations on electrostatic and RF performances of JLSDGM Device

This paper offers a systematic analysis on the impact of work function (WF) variations on electrostatic and radio frequency (RF) performances of nchannel junctionless strained double gate (DG) (n-JLSDGM) metal oxide semiconductor field effect transistor (MOSFET). The study has been performed under othe constant level of design parameters that operates in saturation as a transconductance amplifier, considering the dependence of electrostatic and RF performance on the variation of WF. Furthermore, this paper aims to provide physical insight into the improved electrostatic and RF performances of the proposed n-JLSDGM device. The device layout and characteristics were designed and extracted respectively via a comprehensive 2-D simulation. Device performances such as on-state current (ION), off-state current (IOFF), on-off current ratio, subthreshold swing (SS), intrinsic capacitances, dynamic power dissipation (Pdyn), cut-off frequency (fT) and maximum oscillation frequency (fmax) are intensively investigated in conjunction with WF variations.

Study of Analog/Rf and Stability Investigation of Surrounded Gate Junctionless Graded Channel MOSFET(SJLGC MOSFET)

This paper explores the potential advantage of surrounded gate junctionless graded channel (SJLGC) MOSFET in the view of its Analog, RF performances using ATLAS TCAD device simulator. The impact of graded channel in the lateral direction on the potential, electric field, and velocity of carriers, energy band along the channel is investigated systematically. The present work mainly emphasises on the superior performance of SJLGC MOSFET by showing higher drain current (ID) , transconductance (gm) ,cut off frequency (fT) , maximum frequency of oscillation (fmax) , critical frequency (fK) .The drain current is improved by 10.03 % in SJLGC MOSFET due to the impact of grading the channel. There is an improvement in fT, fmax, fK by 45%, 29% and 18% respectively in SJLGC MOSFET showing better RF Performance. The dominance of the SJLGC MOSFET over SJL MOSFET is further elucidated by showing 74% improvement in intrinsic voltage gain (gm / gds) indicating its better applications in sub threshold region. But the transconductance generation factor of SJLGC MOSFET is less than SJL MOSFET in the subthreshold region. The intrinsic gate delay (ζD) of SJLGC MOSFET is less in comparison to SJL MOSFET due to the impact of lower gate to gate capacitance (CGG) suggesting better digital switching applications. The simulation results reveal that SJLGC MOSFET can be a competitive contender for the coming generation of RF circuits covering a broad range of operating frequencies in RF spectrum.

Highly Stretchable and Durable Nanocomposite Bow-Tie Antenna for Wearable Application

We present a highly stretchable and compact bow-tie antenna which operates at 5 GHz for wearable applications. The dimensions of the bow-tie antenna were 7.9 mm×17.8 mm. The stretchable antenna was fabricated with a composite mixture of silver flake and polymer binder. The composite paste was printed on polyurethane and textile using the screen printing technique. The RF performances, stretchability, bendability, and durability of the antennas were evaluated, which are critical requirements in wearable electronics. The stretchable bow-tie antennas showed excellent RF performances and stretchability up to a stretching strain of 40%. The antennas could be bent up to a bending radius of 20 mm without degrading RF performance. The stretchable antennas also exhibited outstanding mechanical endurance after 10,000 cyclic stretching tests. The antennas were not affected by the presence of the body and showed very stable RF performances, exhibiting promising results for mobile and wearable applications.