Artigos
URI permanente para esta coleçãohttps://repositorio.fei.edu.br/handle/FEI/798
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Resultados da Pesquisa
- Modeling the interface traps-related low frequency noise in triple-gate SOI junctionless nanowire transistors(2019) Trevisoli R.; Doria R.T.; Barraud S.; Pavanello M.A.© 2019 Elsevier B.V.The aim of this work is to propose a semi-analytical model for the low frequency noise caused by interface traps in Triple-Gate Junctionless Nanowire Transistors. The proposed model is based on a drain current model, which includes short channel effects influence. The surface potential and the occupied trap density equations are solved self consistently to obtain the traps influence in the static drain current, which is used to determine the trap-related noise. In this work, the low frequency noise of traps in discrete levels is analyzed. The model has been validated with 3D simulations considering different devices characteristics, biases and trap levels. Experimental results have also been used to demonstrate the model suitability.
- Analysis of the substrate bias effect on the interface trapped charges in junctionless nanowire transistors through low-frequency noise characterization(2017) Doria R.T.; Trevisoli R.; de Souza M.; Barraud S.; Vinet M.; Faynot O.; Pavanello M.A.© 2017 Elsevier B.V.This work presents, for the first time, an experimental analysis of the low-frequency noise and the effective trap density dependence of junctionless nanowire transistors (JNTs) on the substrate bias. The study has been performed for devices with different channel lengths and doping concentrations biased close to the threshold and deep in linear regime. It has been shown that the surface potential of JNTs is strongly influenced by the substrate bias even above threshold. Thus, the drain current noise spectral density and the effective trap density can be improved or degraded depending on the bias applied to the substrate of the devices. Additionally, it is shown that, the variation on the substrate bias enables the evaluation of traps with different activation energy ranges, which is more evident in heavier doped devices due to the higher threshold voltage sensitivity to the substrate bias.
- Low-frequency noise of n-type triple gate FinFETs fabricated on standard and 45 rotated substrates(2013) Doria R.T.; Martino J.A.; Simoen E.; Claeys C.; Pavanello M.A.This paper studies the impact of the 45 substrate rotation on the low-frequency noise (LFN) of triple gate nFinFETs. The overall LFN has been extracted for both standard and 45 substrate rotated devices of several fin widths at different drain and gate voltage biases focusing on their operation in saturation regime. A general view of the mechanisms which govern the low-frequency noise in MOS devices is provided and a brief discussion on the physical origins of the LFN in the evaluated devices is carried out. It has been noted that the LFN in non-rotated (0 rotated) and 45 rotated devices operating in the linear regime shows 1/f behavior independent on the gate bias, whereas in the saturation regime both 1/f and Lorentzian (1/f2) noises are observed. The former one prevails at lower frequencies and the 1/f2 noise at higher ones. In this case, the corner frequency shows an exponential dependence on the gate bias. © 2013 Elsevier Ltd. All rights reserved.
- In-depth low frequency noise evaluation of substrate rotation and strain engineering in N-type triple gate SOI Finfets(2015) Doria R.T.; De Souza M.A.S.; Martino J.A.; Simoen E.; Claeys C.; Pavanello M.A.© 2015 Elsevier B.V. All rights reserved.This work presents an experimental analysis of the low-frequency noise and the effective trap density of conventional, strained, rotated and strained-rotated SOI n-type FinFETs, respectively, for several fin widths biased at different gate voltages. Additionally, the profile of the effective trap density is presented along the depth of the gate dielectric of the devices. It is shown that strained devices present higher noise than conventional ones, independent on the fin width, which can be explained by poorer interface quality observed in strained devices. On the other hand, the low frequency noise of narrow rotated devices, where the main conduction path changes from top to sidewalls, has shown to reduce as the interface integrity is improved by substrate rotation. All the evaluated devices presented 1/f noise as the dominant noise component up to 1 kHz.
- Low-frequency noise and effective trap density of short channel p- and n-types junctionless nanowire transistors(2014) Doria R.T.; Trevisoli R.; De Souza M.; Pavanello M.A.This work presents an evaluation of the Low-Frequency Noise (LFN) exhibited by short-channel Junctionless Nanowire Transistors (JNTs). Unlike in previous works in which only the noise of n-type transistors was evaluated, this paper exhibits an analysis of both the LFN and the effective trap density of n- and p-type JNTs. The low-frequency noise is analyzed in terms of the channel length as well as doping concentration and has shown to be nearly independent on the former parameter when the device is biased above threshold and to decrease with the raise of the latter. Also, carrier number fluctuations dominate the LFN in nMOS JNTs whereas an important mobility fluctuation component is present in the pMOS ones. The effective trap density of JNTs has shown to be in the order of 1019 cm-3 eV-1, presenting its maximum around 1.4 nm away from the silicon/gate dielectric interface independently on the device type or doping concentration. © 2014 Elsevier Ltd. All rights reserved.
- Trap density characterization through low-frequency noise in junctionless transistors(2013) Doria R.T.; Trevisoli R.D.; De Souza M.; Pavanello M.A.This work evaluates, for the first time, the trap density of Junctionless Nanowire Transistors (JNTs) of two technologies produced with different gate dielectrics through the low-frequency noise (LFN) characterization. Along the work, the LFN resultant from both devices was compared in linear and saturation regimes for different gate biases, showing that these devices can exhibit either 1/f or Lorentzian as the dominant noise source depending on the technology and gate bias. Such analysis showed that devices with SiO2 gate dielectric have presented only one corner frequency over the whole frequency range whereas two corner frequencies with different time constants could be observed in devices with HfSiON gate dielectric. The trap density of both devices showed to be similar to the values reported for inversion mode devices in different recent papers, in the order of 1016 cm-3 eV-1 and 1019 cm-3 eV-1, for SiO2 and HfSiON gate dielectrics, respectively.© 2013 Elsevier B.V.All rights reserved.
- The low-frequency noise behaviour of graded-channel SOI nMOSFETs(2007) Simoen E.; Claeys C.; Chung T.M.; Flandre D.; Pavanello M.A.; Martino J.A.; Raskin J.-P.It is shown that the low-frequency noise in graded-channel (GC) SOI nMOSFETs is generally of the flicker or 1/f noise type. The corresponding input-referred noise spectral density is markedly higher than for the conventional uniformly doped or the intrinsic un-doped fully depleted n-channel SOI transistors. However, this increase can only be partially explained by the effective channel length reduction provided by the lightly doped region of the GC structure. It is furthermore demonstrated that the underlying noise mechanism for the GC structures is rather related to carrier number fluctuations compared with mobility fluctuations for the intrinsic or the uniformly doped fully depleted device. It is concluded that for optimal analog performance of GC SOI nMOSFETs, high gain has to be traded off for higher 1/f noise. © 2007 Elsevier Ltd. All rights reserved.