Time Domain and Frequency Analysis of Random Telegraph Signal and the Contributions of G-R Centres to I-V Instabilities in 4H-SiC MESFETs

2006 ◽  
Vol 527-529 ◽  
pp. 1251-1254
Author(s):  
Mohamed Trabelsi ◽  
Nabil Sghaier ◽  
Jean Marie Bluet ◽  
Noureddine Yacoubi ◽  
Gérard Guillot ◽  
...  
Keyword(s):  
Frequency Analysis ◽  
Low Frequency ◽  
Drain Current ◽  
Frequency Noise ◽  
Low Frequencies ◽  
Si Substrates ◽  
Power Spectral ◽  
Parameters Analysis ◽  
Output Characteristics ◽  
Rts Noise

Our work is focused on the identification of defects responsible for current fluctuations at the origin of low frequency noise or random telegraphic signals in 4H-SiC MESFETs on semiinsulating (SI) substrates. We show that devices having instabilities have DC output characteristics with random discrete fluctuations of the drain current. The RTS noise parameters analysis (amplitude, high and low state time durations) as a function of temperature and bias voltage provides the signature of the involved traps (activation energy and cross section both for emission and capture). From the power spectral density of the drain current noise (PSD) we have measured the cut-off frequency of a single trap even at very low frequencies (from 0.1 Hz) and we propose that the noise responsible of RTS fluctuations is a generation-recombination noise. Finally, it is shown that the frequency analysis of the random telegraphic signal is a well-suited tool for the study of single defects in very small devices.

LOW FREQUENCY NOISE IN SUB-0.1μmSiGepMOSFETs, CHARACTERISATION AND MODELING

2004 ◽  
Vol 04 (02) ◽  
pp. L309-L318 ◽  
Author(s):  
KRUNOSLAV ROMANJEK ◽  
GÉRARD GHIBAUDO ◽  
THOMAS ERNST ◽  
JAN A. CHROBOCZEK
Keyword(s):  
Low Frequency ◽  
Hole Mobility ◽  
Drain Current ◽  
Frequency Noise ◽  
Transport Parameters ◽  
Noise Sources ◽  
Interface Charges ◽  
Power Spectral ◽  
Strong Inversion ◽  
Channel Lengths

Drain current-gate voltage, I d ( V g ) characteristics and the power spectral density, PSD , of I d fluctuations were obtained on SiGe channel pMOSFETs and on their Si homologues, for I d intensities varied from deep sub-threshold to strong inversion values. Devices with 2.2nm thick SiO 2 gates and channel lengths 50 nm <L<10μm were used. In heterostructures, the SiGe layers were 20nm thick and buried under 2nm of Si . The data were simulated, assuming a parallel current flow in the interface and the SiGe channels, with associated noise sources. The transport parameters, extracted from I d ( V g ) characteristics, served for calculating the PSD ( I d ) functions. The latter required adjusting the interface trap density and a parameter α c , accounting for the effect of the interface charge fluctua-tions on the hole mobility fluctuations, significant at high levels of trap filling i.e. high I d . We found that the PSD in the SiGe devices was up to 10 times lower than in the Si controls at sufficiently high I d . The simulation, accounting for the data, required a significant lowering of α c for the SiGe channel. That implies that the LFN reduction in SiGe MOSFETs results from a weaker interaction of the SiGe holes with the interface charges. The sub-0.1μm channel devices show a similar noise lowering, in spite of the hole mobility degradation.

1/f Noise Behavior in Pentacene Organic Thin Film Transistors

1999 ◽  
Vol 598 ◽  
Author(s):  
P. V. Necliudov ◽  
D. J. Gundlach ◽  
T. N. Jackson ◽  
S. L. Rumyantsev ◽  
M. S. Shur
Keyword(s):  
Thin Film ◽  
Conducting Polymers ◽  
Thin Film Transistors ◽  
Low Frequency ◽  
Drain Current ◽  
Frequency Noise ◽  
Organic Thin Film ◽  
Amorphous Si ◽  
Parameter Values ◽  
Device Noise

ABSTRACTWe studied the low frequency noise in top-contact pentacene Thin Film Transistors (TFTs). The relative spectral noise density of the drain current fluctuations SI/I2 had a form of 1/f noise in the measured frequency range 1Hz - 3.5kHz.Our studies of the noise dependencies on the gate-source VGS and drain-source VDS voltages showed that the dependencies differed from those observed for conducting polymers and resembled those reported for crystalline Si n-MOSFETs.To compare the device noise level with those of other devices and materials, we extracted the Hooge parameter α. In order to calculate the total number of carriers we used a model simulating the device DC characteristics, similar to that for amorphous Si TFTs. The extracted Hooge parameter was 0.04. For an organic material this is an extremely small value, which is three orders of magnitude smaller that the Hooge parameter values reported for conducting polymers and only several times higher than the values for amorphous Si TFTs.

Low Frequency Noise Annoyance Assessment by Low Frequency Noise Rating (LFNR) Curves

1983 ◽  
Vol 2 (1) ◽  
pp. 20-28 ◽  
Author(s):  
N. Broner ◽  
H.G. Leventhall
Keyword(s):  
Laboratory Experiments ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Low Frequencies ◽  
Noise Annoyance

Over recent years, it has become apparent that low frequency noise annoyance is more widespread than originally believed. Annoyance has occurred where the emitted noise is unbalanced towards the low frequencies even though the dB(A) level has been low. Following laboratory experiments carried out as part of an investigation into low frequency annoyance, combined with field annoyance data, the Low Frequency Noise Rating (LFNR) curves are proposed for the assessment of low frequency noise annoyance complaints.

Low Frequency Absorption of Additively Manufactured Cylinders

2019 ◽  
Author(s):  
Sophie R. Kaye ◽  
Ethan D. Casavant ◽  
Paul E. Slaboch
Keyword(s):  
Low Frequency ◽  
Normal Incidence ◽  
Frequency Noise ◽  
Outer Diameter ◽  
Acoustic Absorption ◽  
Frequency Range ◽  
Large Space ◽  
Low Frequencies ◽  
Cylinder Length ◽  
Hollow Cylinders

Abstract Attenuating low frequencies is often problematic, due to the large space required for common absorptive materials to mitigate such noise. However, natural hollow reeds are known to effectively attenuate low frequencies while occupying relatively little space compared to traditional absorptive materials. This paper discusses the effect of varied outer diameter, and outer spacing on the 200–1600 Hz acoustic absorption of additively manufactured arrays of hollow cylinders. Samples were tested in a 10 cm diameter normal incidence impedance tube such that cylinder length was oriented perpendicular to the incoming plane wave. By varying only one geometric element of each array, the absorption due to any particular parameter can be assessed individually. The tests confirmed the hypothesis that minimizing cylinder spacing and maximizing cylinder diameter resulted in increased overall absorption and produced more focused absorption peaks at specific low frequencies. Wider cylinder spacing produced a broader absorptive frequency range, despite shifting upward in frequency. Thus, manipulating these variables can specifically target absorption for low frequency noise that would otherwise disturb listeners.

Vibration Control of a Rigid and Flexible High-Speed Railway Vehicle

2020 ◽  
Author(s):  
Semiha Türkay ◽  
Aslı S. Leblebici
Keyword(s):  
High Speed ◽  
Low Frequency ◽  
Railway Vehicle ◽  
Allowable Limit ◽  
Low Frequencies ◽  
Railway Line ◽  
Power Spectral ◽  
Spectral Density Functions ◽  
The Right ◽  
Euler Bernoulli Beam

Abstract In this paper, the vertical carbody dynamics of the railway vehicle excited by random track inputs are investigated. The multi-objective ℋ∞ controllers for carbody weight of the actual, heavy and a mass confined in a polytopic range have been designed with the aim of reducing the wheel forces, heave, pitch and roll body accelerations of the vehicle. Later, the carbody mass is modelled as a free-free Euler Bernoulli beam and the low frequency flexural vibrations of the train body are examined. An omnibus ℋ∞ controller is synthesized to suppress both the rigid and low frequencies flexible modes of the railway vehicle. The performances of the ℋ∞ controllers are verified by using the passive and active suspension responses on the right and left rail track disturbances that are represented by the power spectral density functions authenticated for the stochastic real track data collected from the Qinhuangdao-Shenyang passenger railway line in China. Simulation results showed that all controllers exhibit a very good performance by effectively reducing the car-body accelerations in vicinity of the resonanat frequencies while keeping the wheel-rail forces in the allowable limit.

scholarly journals Noise Characterization of Vortex-State GMR Sensors with Different Free Layer Thicknesses

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 1013
Author(s):  
Herbert Weitensfelder ◽  
Hubert Brueckl ◽  
Armin Satz ◽  
Dieter Suess
Keyword(s):  
Spin Valve ◽  
Low Frequency ◽  
Vortex State ◽  
Frequency Noise ◽  
Free Layer ◽  
Low Frequencies ◽  
Gmr Sensors ◽  
Noise Characterization ◽  
Higher Sensitivity

The spin valve principle is the most prominent sensor design among giant- (GMR) and tunneling (TMR) magnetoresistive sensors. A new sensor concept with a disk shaped free layer enables the formation of a flux-closed vortex magnetization state if a certain relation of thickness to diameter is given. The low frequency noise of current-in-plane GMR sensing elements with different free layer thicknesses at different external field strengths has been measured. The measurements of the 1/f noise in external fields enabled a separation of magnetic and electric noise contributions. It has been shown that while the sensitivity is increasing with a decreasing element thickness, the pink noise contribution is increasing too. Still the detection limit at low frequencies is better in thinner free layer elements due to the higher sensitivity.

Investigation of 1/f Noise and Superimposed RTS Noise in Ti–Au/n-Type GaAs Schottky Barrier Diodes

2015 ◽  
Vol 14 (04) ◽  
pp. 1550041 ◽  
Author(s):  
Alexey V. Klyuev ◽  
Arkady V. Yakimov
Keyword(s):  
Gaussian Noise ◽  
Schottky Diodes ◽  
Low Frequency ◽  
Frequency Noise ◽  
Noise Component ◽  
Burst Noise ◽  
Noise Characteristics ◽  
Total Noise ◽  
Processing Techniques ◽  
Rts Noise

Low frequency noise characteristics of Schottky diodes are investigated. Two noise components were found in experimental noise records: random telegraph signal (RTS), caused by burst noise, and 1/f Gaussian noise. The noise is sampled and recorded on a PC. Then, in addition to the spectrum, the probability density function (pdf) of the total noise is analyzed. In the case of the mixture of the burst noise and Gaussian (1/f) noise, the pdf has two maxima separated by a local minimum. Extraction of burst noise component from Gaussian noise background was performed using the pdf, standard signal detection theory, and advanced signal-processing techniques. It is concluded that the RTS noise and 1/f noise have different physical origins in Schottky diodes. The raw noise is split into two components. One appeared to be burst noise with a Lorentzian-like spectral shape. The other component is 1/f noise. Having extracted 1/f noise, we have studied the dependence of noise spectral values on the current across the diode.

Temperature Dependence of Low Frequency Noise in Silicon on Insulator Tunneling Field Effect Transistor

2020 ◽  
Vol 20 (8) ◽  
pp. 4699-4703
Author(s):  
Hyun-Dong Song ◽  
Hyeong-Sub Song ◽  
Sunil Babu Eadi ◽  
Hyun-Woong Choi ◽  
Ga-Won Lee ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Low Frequency ◽  
Drain Current ◽  
Silicon On Insulator ◽  
Frequency Noise ◽  
Increase With Increase ◽  
Effect Transistor ◽  
Insulator Substrate

In this work, noise mechanism of a tunneling field-effect transistor (TFET) on a silicon-on-insulator substrate was studied as a function of temperature. The results show that the drain current and subthreshold slope increase with increase in temperature. This temperature dependence is likely caused by the generation of greater current flow owing to decreased silicon band gap and leakage. Further, the TFET noise decreases with increase in temperature. Therefore, the effective tunneling length between the source and the channel appears to decrease and Poole–Frenkel tunneling occurs.

Inadequate Standards Currently Applied by Local Authorities to Determine Statutory Nuisance from LF and Infrasound

2003 ◽  
Vol 22 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Hazel Guest
Keyword(s):  
Local Authority ◽  
Low Frequency ◽  
Measurement Information ◽  
Frequency Noise ◽  
Local Authorities ◽  
Low Frequencies ◽  
Specific Effects ◽  
Basic Understanding

Knowledge of the latest results in Low Frequency Noise (LFN) and infrasound research are not being transmitted, either to government whose job it is to legislate on standards of noise and vibration, or to local authority officers whose job it is to look into complaints and enforce standards. The dismissal of complaints is frequently based on inappropriate techniques such as the application of A-weighting, a lack of understanding of vibration transmission including building resonance, and a lack of basic understanding about the perception of low frequencies by complainants, for instance the lowering of the lower audibility threshold arising from exposure. This paper asks those involved in research to ensure that their relevant findings are more widely disseminated, along with advice to legislators and local authorities on measurement, information on LF and infrasound resonance in buildings, recommendations for appropriate standards to be used in assessing LF and infrasound as a Statutory Nuisance, and information about the effects of long-term exposure. There is a need for more research in situ into specific effects.

Low Frequency Noise in 4H-SiC MOSFETs

2009 ◽  
Vol 615-617 ◽  
pp. 817-820 ◽  
Author(s):  
Sergey L. Rumyantsev ◽  
Michael S. Shur ◽  
Michael E. Levinshtein ◽  
Pavel A. Ivanov ◽  
John W. Palmour ◽  
...  
Keyword(s):  
Flicker Noise ◽  
Low Frequency ◽  
Drain Current ◽  
Localized States ◽  
Conduction Band Edge ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Channel Mobility ◽  
Strong Inversion ◽  
First Time

Low-frequency noise in 4H-SiC MOSFETs has been measured for the first time. At drain currents varying from deep subthreshold to strong inversion, the 1/f (flicker) noise dominated at frequencies 1 - 105 Hz. The dependence of relative spectral noise density, , on drain current Id (at a constant drain voltage Vd) differs qualitatively from that in Si MOSFETs. In Si MOSFETs, ~ 1/ in strong inversion, whereas tends to saturate in sub-threshold. In 4H-SiC MOSFETs under study, ~ 1/ over the whole range of currents from deep sub-threshold to strong inversion. Similar noise behavior is often observed in poly- or a-Si TFTs. The effective channel mobility in 4H-SiC MOSFETs, 3 - 7 cm2/Vs, is also as low as that in TFTs. Both noise behavior and transport properties of 4H-SiC MOSFETs are explained, analogously to TFTs, by a high density of localized states (bulk and interface) near the conduction band edge in the ion implanted p-well.

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