Low Frequency Noise In n-Type Gallium Nitride

1998 ◽  
Vol 512 ◽  
Author(s):  
N. Dyakonova ◽  
M. Levinshtein ◽  
S. Contreras ◽  
W. Knap ◽  
B. Beaumont ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
Spectral Density ◽  
Photon Energy ◽  
Electron Concentration ◽  
Low Frequency ◽  
Current Noise ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Frequency Range ◽  
First Time

ABSTRACTLow frequency noise has been investigated in hexagonal n-type GaN with equilibrium electron concentration n ∼ 1017 cm−3 at T=300 K. The frequency and temperature dependencies of the spectral density of the current noise, SI, have been studied in the frequency range f from 20 Hz to 20 kHz. Over the whole temperature range from T=80K to 400K the SI(f) dependence is very close to 1/f. The value of the Hooge constant, α, is very large: α ∼ 5 – 7 and is found to be temperature independent. The effects of illumination on the low frequency noise in GaN are studied for the first time. The noise is unaffected by illumination with photon energy Eph < Eg, while band-to band illumination (Eph∼Eg ) influences the low frequency noise, increasing the noise at higher temperatures, and decreasing it at lower temperatures.

scholarly journals Origin of the Low-Frequency Noise in the Asymmetric Self-Cascode Structure Composed by Fully Depleted SOI nMOSFETs

2017 ◽  
Vol 12 (2) ◽  
pp. 62-70
Author(s):  
Rafael Assalti ◽  
Rodrigo T. Doria ◽  
Denis Flandre ◽  
Michelly De Souza
Keyword(s):  
Spectral Density ◽  
Gate Voltage ◽  
Low Frequency ◽  
Drain Current ◽  
Current Noise ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Noise Spectral Density ◽  
Fully Depleted ◽  
Self Cascode

In this paper the origin of low-frequency noise in the Asymmetric Self-Cascode (A-SC) structure composed by Fully Depleted SOI nMOSFETs is investigated through experimental results. It is shown that the predominant noise source of the A-SC structure is linked to carrier number fluctuations, being governed by the noise generated in the transistor near the source. Larger channel doping concentrations degrade the quality of the Si-SiO2 interface and the gate oxide, which causes an increase of the normalized drain current noise spectral density, just as the reduction of the gate voltage overdrive, since there are few carriers in the channel. The A-SC structures have showed higher noise compared with single transistors. In saturation regime, the increase of the gate voltage overdrive has incremented the corner frequency, shifting the g-r noise to higher frequencies. Besides that, the normalized noise has been significantly increased when compared with the linear regime due to the rise of the drain current noise spectral density.

scholarly journals Low Frequency Noise Remove from EEG Signal

2020 ◽  
Vol 9 (1) ◽  
pp. 1510-1513
Keyword(s):  
Human Brain ◽  
Random Noise ◽  
Low Frequency ◽  
Frequency Noise ◽  
Eeg Signal ◽  
Low Frequency Noise ◽  
Frequency Range ◽  
Average Value ◽  
Different Types ◽  
The Brain

The electrical activity of the brain recorded by EEG which used to detect different types of diseases and disorders of the human brain. There is contained a large amount of random noise present during EEG recording, such as artifacts and baseline changes. These noises affect the low -frequency range of the EEG signal. These artifacts hiding some valuable information during analyzing of the EEG signal. In this paper we used the FIR filter for removing low -frequency noise(<1Hz) from the EEG signal. The performance is measured by calculating the SNR and the RMSE. We obtained RMSE average value from the test is 0.08 and the SNR value at frequency(<1Hz) is 0.0190.

Low-frequency noise control using layered granular aerogel and limp porous media

2021 ◽  
Vol 263 (4) ◽  
pp. 2724-2729
Author(s):  
Yutong Xue ◽  
Amrutha Dasyam ◽  
J. Stuart Bolton ◽  
Bhisham Sharma
Keyword(s):  
Noise Control ◽  
Glass Fibers ◽  
Low Frequency ◽  
Normal Incidence ◽  
Frequency Noise ◽  
Fibrous Materials ◽  
Low Frequency Noise ◽  
Frequency Range ◽  
Fibrous Media ◽  
Impedance Tube Method

The acoustic absorption of granular aerogel layers with a granule sizes in the range of 2 to 40 μm is dominated by narrow-banded, high absorption regions in the low-frequency range and by reduced absorption values at higher frequencies. In this paper, we investigate the possibility of developing new, low-frequency noise reduction materials by layering granular aerogels with traditional porous sound absorbing materials such as glass fibers. The acoustic behavior of the layered configurations is predicted using the arbitrary coefficient method, wherein the granular aerogel layers are modeled as an equivalent poro-elastic material while the fibrous media and membrane are modeled as limp media. The analytical predictions are verified using experimental measurements conducted using the normal incidence, two-microphone impedance tube method. Our results show that layered configurations including granular aerogels, fibrous materials, and limp membranes provide enhanced sound absorption properties that can be tuned for specific noise control applications over a broad frequency range.

Effect of Ge-Nanoislands on the Low-Frequency Noise in Si/SiOx/Ge Structures

2013 ◽  
Vol 854 ◽  
pp. 21-27 ◽  
Author(s):  
N.P. Garbar ◽  
Valeriya N. Kudina ◽  
V.S. Lysenko ◽  
S.V. Kondratenko ◽  
Yu.N. Kozyrev
Keyword(s):  
High Surface ◽  
Low Frequency ◽  
Noise Model ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Physical Processes ◽  
Noise Sources ◽  
Noise Component ◽  
First Time ◽  
Noise Models

Low-frequency noise of the structures with Ge-nanoclusters of rather high surface density grown on the oxidized silicon surface is investigated for the first time. It was revealed that the 1/f γ noise, where γ is close to unity, is the typical noise component. Nevertheless, the 1/f γ noise sources were found to be distributed nonuniformly upon the oxidized silicon structure with Ge-nanoclusters. The noise features revealed were analyzed in the framework of widely used noise models. However, the models used appeared to be unsuitable to explain the noise behavior of the structures studied. The physical processes that should be allowed for to develop the appropriate noise model are discussed.

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.

Impact of Proton Irradiation on Power 4H-SiC MOSFETs

2020 ◽  
Vol 1004 ◽  
pp. 1074-1080
Author(s):  
Alexander A. Lebedev ◽  
Vitalii V. Kozlovski ◽  
Leonid Fursin ◽  
Anatoly M. Strel'chuk ◽  
Mikhail E. Levinshtein ◽  
...  
Keyword(s):  
Proton Irradiation ◽  
Removal Rate ◽  
Low Frequency ◽  
Frequency Noise ◽  
Electrical Characteristics ◽  
Low Frequency Noise ◽  
Frequency Range ◽  
Maximum Value ◽  
Noise Spectroscopy ◽  
Noise Density

Impact of 15 MeV proton irradiation on electrical characteristics and low frequency noise has been studied in high-power vertical 4H-SiC MOSFETs of 1.2 kV-class at doses 1012 £ F £ 1014 cm-2. The maximum value of the field-effect mobility µFЕ depends weakly on F up to F = 2×1013 cm-2. At F = 4×1013 cm-2, the character of the µFЕ(Vg) dependence changes radically. The maximum µFЕ decreases approximately threefold. The dose Fcr corresponding to the complete degradation of the device is about 1014 cm-2. It can be estimated as Fcr» he/n0, where he is the electron removal rate and n0 is the initial electron concentration in the drift layer. In the entire frequency range of analysis f, gate voltages, and drain-source biases, the frequency dependence of the current spectral noise density SI(f) follows the law SI ~ 1/f. From the data of noise spectroscopy, the density of traps in the gate oxide Ntv has been estimated. In non-irradiated structures, Ntv » 5.4×1018 cm-3eV-1. At Ф = 6×1013 cm-2, the Ntv value increases to Ntv » 7.2×1019cm-3eV-1. The non-monotonic behavior of the output current Id and the level of low frequency noise on dose F has been demonstrated.

RESEARCH AND MAPPING OF LOW FREQUENCY NOISE GENERATED BY POWER PLANTS OF INDUSTRIAL ENTREPRISES

Akustika ◽  
2021 ◽  
pp. 103
Author(s):  
Andrey Vasilyev
Keyword(s):  
Power Plants ◽  
Low Frequency ◽  
Environmental Noise ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Frequency Range ◽  
Noise Mapping ◽  
Industrial Enterprises ◽  
Noise Measurements ◽  
Urban Territory

Environmental noise level from industrial enterprises is constantly increasing, especially in low frequency range. This paper presents the results of research and mapping of low frequency noise generated by power plants of industrial enterprises. Environmental noise mapping results of urban territory of Samara region of Russia are also presented. Results of noise measurements during industrial enterprises operation (on the example of “KuibyshevAzot” company) are showing that in some measuring points there were exceeding values compared with Russian sanitary norms requirements. The most serious problem is low frequency noise impact.

1/f NOISES OF HOMOPOLAR AND HETEROPOLAR SEMICONDUCTORS

2000 ◽  
Vol 14 (07) ◽  
pp. 751-760 ◽  
Author(s):  
F. V. GASPARYAN ◽  
S. V. MELKONYAN ◽  
V. M. AROUTIOUNYAN ◽  
H. V. ASRIYAN
Keyword(s):  
Experimental Data ◽  
Spectral Density ◽  
Temperature Dependence ◽  
Conduction Electron ◽  
Optical Phonon ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Noise Spectral Density ◽  
Analytical Expressions

The low-frequency noise spectral density with the 1/f spectrum for homopolar and heteropolar semi-conductors is theoretically obtained taking into account conduction electron–optical phonon interactions. The analytical expressions of the spectral density and Hooge's α H parameter are presented. The analytical temperature dependence of Hooge's parameter is compared with experimental data for n-Si and n-GaAs.

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