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Normalized 1/f contribution to the low-frequency noise spectrum at 1 Hz as a function of d ch for Al 0.3 Ga 0.7 As/In 0.25 Ga 0.75 As/GaAs HEMTs, at 77 K and 300 K. The drain-source voltage applied was 5 mV and the temperature, 300 K. The gate voltage was chosen to have a drain current of 1 A.
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Low‐frequency noise measurements have been performed in the linear range of the I‐V characteristics of pseudomorphic Al 0.3 Ga 0.7 As/In 0.25 Ga 0.75 As/GaAs high electron mobility transistors (HEMTs) grown by molecular beam epitaxy with different channel thicknesses. The results obtained show that the 1/f noise in such devices depends greatly on c...
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AlxGa1- xN/GaN high electron mobility transistor (HEMT) structures grown by ammonia-source molecular beam epitaxy (MBE) are focused-ion-beam implanted with 300 keV Gd-ions at room temperature. The two-dimensional electron gas (2DEG) of these HEMT structures is located 27 nm underneath the sample surface. At 4.2 K, current-voltage characteristics ac...
Citations
... 27 Starting from the ladder network model in Fig. 3(a), the analysis considers how the current divides between individual (14) are less than V DS, MOD due to voltage drops across R int elements in the ladder network and are evaluated for representative cases using an LTSPICE circuit simulator. This analysis used R int , and R chi from Eq. (6) 46,47 A lack of film uniformity in such systems generally leads to current crowding on a microscopic scale, leading to high noise. Although devices using exfoliated 2D TMDs is less likely to suffer from these issues, however, the same materials grown using large scale techniques such as chemical vapor deposition could experience such adversaries. ...
In field-effect transistors (FETs) with two-dimensional (2D) transition metal dichalcogenide channels, the dependence of field-effect mobility on atomic layer thickness has been studied and interpreted in terms of interface scattering and interlayer coupling resistance (R int). However, a model for 1/f noise, such as in MoS 2 and in MoSe 2 FETs, for various contact metals and layer number thicknesses has not been reported. In this work, we have experimentally studied current-voltage and 1/f noise on MoS 2 and MoSe 2 FETs with source and drain contacts of high and low work function metals to understand both the mobility and the noise behavior. We have developed a noise model incorporating layer number dependent Hooge parameters and R int. The noise and mobility models utilize screening lengths for charge, mobility, and Hooge parameter to describe the variation of these quantities with a layer number. Using our single model topology with appropriate fitting parameters for each material and each contact metal, the model captures the experimentally observed layer thickness dependence of the Hooge parameter. Our noise analysis is fully comprehensive and, hence, could be applied to any 2D layered systems.
... These phenomena limit the performance for application such as nonlinear circuits that have noise upconversion, and ultrawide-bandwidth circuits. Even though the low-frequency noise characteristics have been intensively studied [8]- [11], further study is necessary to fully understand the behavior of the noise. ...
... Then it is necessary to consider the contribution of other mechanism. One of the plausible origins is the real-space transfer of electrons over the hetero-barrier [11]. The real-space transfer of the electrons between the channel and the AlGaAs barrier layer will cause the fluctuation of electron density resulting in the G-R noise. ...
The low-frequency noise of InGaAs pseudomorphic HEMTs fabricated on GaAs substrate was studied. The dependence of the noise spectral density on the gate voltage indicates that the channel of the device dominates the low-frequency noise. Generation-recombination (G-R) noise was observed in the form of bulges superimposed on a background of 1/f. The activation energy of the G-R noise was 0.32-0.39 eV which is close to that of the DX center suggesting that the origin of the G-R noise is the DX center in the AlGaAs barrier layer. Little bulge was observed in the gate current noise of the HEMTs with large InAs mole fractions of 0.4 and 0.5. Generation of the traps with different time constant can explain this behavior.
... The values of α extracted from the noise spectra for the HD JFET are of the order of 2 × 10 -3 . This value is two orders of magnitude larger than that for a 2D MESFET [7] and is comparable to the values for some AlGaAs/InGaAs HEMTs [8] and AlGaN/GaN HFETs [9,10]. The reason for the relatively high noise level in the HD JFET can be explained by the high gate leakage current (up to 0.1 µ A) [3 -5]. ...
An investigation is presented into the low frequency noise in GaAs
heterodimensional junction field effect transistors (HD JFETs) at room
and elevated temperatures. The Hooge parameter at zero gate bias was
calculated to be 2×10<sup>-3</sup> for the devices. The
temperature dependence of the noise was used to determine the trap level
with an activation energy of 0.7 eV
In this paper we have proposed a procedure for HEMT's diagnostic based on measurements of phase noise of test oscillator. From phase noise measurement in high frequency range we have estimated parameters of low frequency noise using a methodology based on the theory of noise up conversion, and then we have been used these parameters in diagnostic of transistors and to propose a criteria for selection of them. Suggested procedure is suitable for those who are interfered in applying HEMT's in high frequency circuits, because it enables to use noise spectroscopy in HEMT's diagnostic without direct measurements of low frequency noise. Experimental results that illustrate applying of procedure are given.
We present an equivalent circuit model for the low-frequency noise (LFN)
in high electron mobility transistors (HEMTs). Our model correctly
describes the dependence of LFN on gate voltage under low-drain-voltage
conditions. Our model also allows us to investigate the location of the
noise sources in HEMTs and leads to the fact that LFN arising from the
extrinsic region is not negligible but dominant at a higher gate
voltage.
We have investigated the effects of a high-field region on low-frequency noise (LFN) in AlGaAs/InGaAs HEMTs using a two-region model and experiments. The negative cross-correlation between the LFN generated from a low-field region and that from a high-field region is found for the first time. This negative cross-correlation depends on gate and drain voltages, and increases with gate voltage. Due to this negative cross-correlation, the observed LFN is almost constant because the cross-correlation cancels out the increase in the LFN generated from the low-field region.
The surplus low-frequency noise (LFN) caused by substrate current is investigated for high electron mobility transistors (HEMTs). The substrate current increases with decreasing the substrate thickness, which causes the surplus LFN. It is found that the surplus LFN is proportional to the square of the substrate current, and becomes dominant in the case of a thinner substrate. We also discuss the restriction on the substrate thickness from the viewpoint of LFN.
We report on the low frequency [1/f and generation-recombination (GR)] noise in InAlAs/InGaAs modulation doped field effect transistors with a 50-nm gate length. The characteristic capture and emission times of the GR noise depended on the gate voltage. Measurements of the noise as a function of the gate voltage showed that the gate leakage current, contacts, and ungated sections of the channel did not contribute to the 1/f noise. The gate voltage dependence of the 1/f noise agreed well with the model of number of carriers fluctuations as a source of the 1/f noise. An effective density of traps responsible for the 1/f noise was found to be Deff ≈ 2.7×1012 cm−2 eV−1.
Low frequency noise in the two‐dimensional metal‐semiconductor field effect transistor (2D‐MESFET) is reported. It is shown that the noise level S is rather small. At room temperature the value of Hooge constant α was about 2×10−5 for frequency f=20 Hz. The frequency dependence of the relative spectral density of current fluctuations SI/I2 at 300 K was close to S∼1/f0.6 in the frequency range 20 Hz–20 kHz. Two local maxima were observed in the temperature dependence of S in the ranges 100–180 K and 200–300 K. © 1996 American Institute of Physics.
The use of noise to determine the properties of defects in crystalline matter and the types of dynamical coherence in various glassy structures is described. Some introduction is given to traditional and new analysis tools, especially ones using non-Gaussian statistics. Many examples are provided in glasses, metals with defects, spin glasses, charge-density waves, disordered domain structures, magnetic vortices in superconductors, and related areas. The focus is on quasi-equilibrium effects, but driven noise, e.g. the Barkhausen effect, is also discussed. The examples range from testing theories of the spin-glass state to in situ testing of the stress in steel cables.
