1,720,966 research outputs found
Numerical simulation of advanced CMOS and beyond CMOS devices
Full text linkLo scaling dei dispositivi elettronici e l'introduzione di nuove opzioni tecnologiche per l'aumento delle prestazioni richiede un costante supporto dal punto di vista della simulazione numerica. Questa tesi si inquadra in tale ambito ed in particolare si prefigge lo scopo di sviluppare due tool software completi basati su tecniche avanzate al fine di predire le prestazioni di dipositivi nano-elettronici progettati per i futuri nodi tecnologic
Surface-Roughness-Induced Variability in Nanowire InAs Tunnel FETs
No full textWe present a comparative study of the surfaceroughness
(SR)-induced variability at low supply voltage
VDD = 0.3 V in nanowire InAs tunnel FETs and strained-silicon
(sSi)MOSFETs. By exploiting a 3-D full-quantum approach based
on the Non-Equilibrium Green’s Function formalism, we show
that the Ion variability in InAs tunnel FETs is much smaller
than the Ioff variability, whereas for VDD = 0.3 V, the sSi MOSFETs
working in the subthreshold regime present similar Ion
and Ioff variability. We explain the smaller Ion compared with
Ioff variability of InAs tunnel FETs by noting that in the source
depletion region, where tunnelingmainly occurs for VGS = VDD,
microscopic subband fluctuations induced by SR are small compared
to macroscopic band bending due to the built-in potential
of the source junction and to the gate bias. This results in SR-induced
variability that is larger in InAs tunnel FETs than in sSi
MOSFETs
Modeling of Field-Effect-Transistors with Strained and Alternative Channel Materials
No full textIn this paper we present a review of the modeling of strain effects in nano-scale transistors and we describe different approaches that can be followed in order to include the effect of strain in both conventional and innovative devices. We first describe the mathematical framework for the modeling of strain and then we present two important case-studies where we have successfully emploied advanced modeling techniques in order to investigate the effect of strain in germanium-based MOSFETs and in InAs Tunnel-FETs
On the Surface-Roughness Scattering in Biaxially Strained n- and p-MOS Transistors
No full textElectron- and hole-mobility enhancements in biaxially
strained metal–oxide–semiconductor transistors are still a
matter for active investigation, and this brief presents a critical
examination of a recently proposed interpretation of the experimental
data, according to which the strain significantly modifies
not only the root-mean-square value but also the correlation
length of the surface-roughness spectrum.We present a systematic
comparison between comprehensive numerical simulations and
experiments, which supports such an interpretation
Impact of Interface Traps on the IV Curves of InAs Tunnel-FETs and MOSFETs: A Full Quantum Study
No full textWe present the first computational study employing a full
quantum transport model to investigate the effect of interface
traps in nanowire InAs Tunnel FETs and MOSFETs. To this
purpose, we introduced a description of interface traps in a
simulator based on the NEGF formalism and on a 8×8 k·p
Hamiltonian and accounting for phonon scattering. Our results
show that: (a) even a single trap can detereorate the inverse
sub-threshold slope (SS) of a nanowire InAs Tunnel FET; (b)
the inelastic phonon assisted tunneling (PAT) through interface
traps results in a temperature dependence of the Tunnel FETs
IV characteristics; (c) the impact of interface traps on Iof f is
larger in Tunnel FETs than in MOSFETs; (d) interface traps
represent a sizable source of device variability
A Multi-Subband Monte Carlo study of electron transport in strained SiGe n-type FinFETs
No full textThis paper reports a simulation study investigating
the drive current in the prototypical SiGe n-type FinFET depicted
in Fig.1 and for different values of the Ge content x in the
Si(1−x)Gex active layer. To this purpose we performed strain simulations,
band-structure calculations and Multi-Subband Monte
Carlo transport simulations accounting for the effects of the Ge
content on both the band-structure and scattering rates in the
transistor channel. Our results suggest that the largest on-current
may be obtained with a simple Si active layer
Simulation study of the on-current improvements in Ge and sGe versus Si and sSi nano-MOSFETs
No full textThis paper employs a state-of-the-art semi-classical transport model for inversion layers to analyze the Ion in Si, sSi, Ge and sGe n- and p-MOSFETs by accounting for all the relevant scattering mechanisms (including the remote surface-optical phonons (SOph) and remote Coulomb scattering (remQ) related to high-κ dielectrics), in which strain is implicitly introduced by a modification of the band structure. Our models are first validated against experiments for both mobility and IDS in nanoscale transistors. Then the Ion in Ge and Si MOSFETs is compared for different crystal orientations and strain conditions
Drain current improvements in uniaxially strained p-MOSFETs: A Multi-Subband Monte Carlo study
No full textThis paper presents a Multi-Subband Monte Carlo study of the drain current improvements in uniaxially,
compressively strained (001)/[110] p-MOSFETs and analyzes the ingredients through which the strain
improves the long channel mobility as well as the ION of nanoscale transistors. We first discuss the strain
induced mobility enhancement and then address the effects of the strain on the ION. In particular, our
results show that compressive stress in (001)/[110] p-MOS transistors increases the ION by improving
both the injection velocity and the back-scattering coefficient and that, furthermore, the back-scattering
coefficients of the p-MOS transistors have values comparable to those of n-MOS devices with similar
channel length
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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