Random Telegraph Noise Research Articles

Methods in fluctuation (noise) spectroscopy and continuous analysis for high-throughput measurements

Abstract Fluctuation (noise) spectroscopy is widely used to investigate the low-frequency dynamics of charge carriers in condensed-matter systems, aiming to (i) improve the performance of micro- and nanoscale electronic devices and sensors, and (ii) use ‘noise as a signal’ in order to fundamentally investigate the microscopic motion and transitions of charge carriers coupled to the low-lying excitations in solids. Here, we focus on measurements of the ubiquitous 1 / f -type fluctuations, often composed by a superposition of (independent or correlated) two-level systems each giving rise to a Lorentzian spectrum, denoted random telegraph noise in the time domain. We briefly review the basic concepts of noise and fluctuations and give a comprehensive overview of state-of-the-art measuring techniques, using both commercially available signal analyzers and custom software in order to perform the spectral analysis of the recorded time signals, and critically evaluate their advantages and drawbacks. We describe how to use fast data acquisition devices in a cross-correlation setup providing additional quantitative information on the magnitude of uncorrelated instrument noise, and demonstrate the mathematical intricacies of extracting the noise spectra. We introduce a new method for high-throughput measurements by automated spectral analysis based on the concept of Continuous Analysis. We demonstrate the potential of this technique, working towards a FAIR data workflow, by measurements of magnetic flux noise within the hysteresis loop of ferromagnetic nanostructures.

Spatially resolved random telegraph fluctuations of a single trap at the Si/SiO2 interface

We use electrostatic force microscopy to spatially resolve random telegraph noise at the Si/SiO2 interface. Our measurements demonstrate that two-state fluctuations are localized at interfacial traps, with bias-dependent rates and amplitudes. These two-level systems lead to correlated carrier number and mobility fluctuations with a range of characteristic timescales; taken together as an ensemble, they give rise to a [Formula: see text] power spectral trend. Such individual defect fluctuations at the Si/SiO2 interface impair the performance and reliability of nanoscale semiconductor devices and will be a significant source of noise in semiconductor-based quantum sensors and computers. The fluctuations measured here are associated with a four-fold competition of rates, including slow two-state switching on the order of seconds and, in one state, fast switching on the order of nanoseconds which is associated with energy loss.

Quantum decoherence dynamics in stochastically fluctuating environments.

We theoretically study the decoherence of a two-level quantum system coupled to noisy environments exhibiting linear and quadratic fluctuations within the framework of a stochastic Liouville equation. It is shown that the intrinsic energy levels of the quantum system renormalize under either the linear or quadratic influence of the environmental noise. In the case of quadratic dependence, the renormalization of the energy levels of the system emerges even if the environmental noise exhibits stationary statistical properties. This is in contrast to the case under linear influence, where the intrinsic energy levels of the system renormalize only if the environmental noise displays nonstationary statistics. We derive the analytical expressions of the decoherence function in the cases where the fluctuation of the frequency difference depends linearly and quadratically on the nonstationary Ornstein-Uhlenbeck noise (OUN) and random telegraph noise (RTN) processes, respectively. In the case of the linear dependence of the OUN, the environmental nonstationary statistical property can enhance the dynamical decoherence. However, the nonstationary statistics of the environmental noise can suppress the quantum decoherence in this case under the quadratic influence of the OUN. In the presence of the RTN, the quadratic influence of the environmental noise does not give rise to decoherence but only causes a determinate frequency renormalization in dynamical evolution. The environmental nonstationary statistical property can suppress the quantum decoherence of the case under the linear influence of the RTN.

Evidence of contact-induced variability in industrially-fabricated highly-scaled MoS2 FETs

Evidence of microscopic inhomogeneities of the side source/drain contacts in 300 mm wafer integrated MoS2 field-effect transistors is presented. In particular, the presence of a limited number of low Schottky barrier spots through which channel carriers are predominantly injected is demonstrated by the dramatic current changes induced by individual charge traps located near the source contact. Two distinct types of “contact-impacting traps” are identified. Type-1 trap is adjacent to the contact interface and exchanges carriers with the metal. Its impact is only observable when the adjacent contact is the reverse-biased FET source and limits the channel current. Type-2 trap is located in the AlOx gate oxide interlayer, near the source contact, and exchanges carriers with the channel. Its capture/emission time constants exhibit both a gate and drain bias dependence due to the high sensitivity of the contact regions to the applied lateral and vertical fields. Unlike typical channel-impacting oxide traps, both types of reported defects affect the Schottky barrier height and width rather than the threshold voltage and result in giant random telegraph noise (RTN). These observations indicate that the contact quality and geometry play a fundamental role in the ultimate scaling of 2D FETs.

Observation of the sliding phason mode of the incommensurate magnetic texture in Fe/Ir(111)

The nanoscopic magnetic texture forming in a monolayer of iron on the (111) surface of iridium, Fe/Ir(111), is spatially modulated and uniaxially incommensurate with respect to the crystallographic periodicities. As a consequence, a low-energy magnetic excitation is expected that corresponds to the sliding of the texture along the incommensurate direction, i.e., a phason mode, which we explicitly confirm with atomistic spin simulations. Using scanning tunneling microscopy (STM), we succeed to observe this phason mode experimentally. It can be excited by the STM tip, which leads to a random telegraph noise in the tunneling current that we attribute to the presence of two minima in the phason potential due to the presence of disorder in our sample. This provides the prospect of a floating phase in cleaner samples and, potentially, a commensurate-incommensurate transition as a function of external control parameters.

Bias polarity dependent low-frequency noise in ultra-thin AlOx-based magnetic tunnel junctions

We exploit bias polarity dependent low-frequency noise (LFN) spectroscopy to investigate charge transport dynamics in ultra-thin AlOx-based magnetic tunnel junctions (MTJs) with bipolar resistive switching (RS). By measuring the noise characteristics across the entire bias voltage range of bipolar RS, we find that the voltage noise level exhibits an bias polarity dependence. This distinct feature is intimately correlated with reconfiguring of the inherently existing oxygen vacancies (VO..\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${V}_{O}^{..}$$\\end{document}) in as-grown MTJ devices during the SET and RESET switching processes. In addition, we observe two-level random telegraph noise (RTN) with a longer and shorter tunneling length in the high resistance state (HRS) and low resistance state (LRS) at a low bias voltage. The intrinsic voltage fluctuations of RTN arise from the dynamics of electron trapping/de-trapping processes at the VO..\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${V}_{O}^{..}$$\\end{document}-related trap sites. Notably, the RTN magnitude is similar in LRS but nonidentical in that of HRS for different bias polarity. These findings strongly suggest that the inherent VO..\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${V}_{O}^{..}$$\\end{document} are distributed near the top CoFe/AlOx interface in the HRS; in contrast, they are expanded to the middle region of the AlOx in the LRS. More importantly, we demonstrate that the location and distribution of the inherent VO..\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${V}_{O}^{..}$$\\end{document} can be electrically tuned, which plays an essential role in the charge transport dynamics in the ultra-thin AlOx-based MTJs and have significant implications for developing emergent memory and logic devices.

The Drain Bias Modulation Effect of Random Telegraph Noise in Gate-All-Around FETs for Cryogenic Applications

The Drain Bias Modulation Effect of Random Telegraph Noise in Gate-All-Around FETs for Cryogenic Applications

Random telegraph noise characteristic of nonvolatile resistive random access memories based on optical interference principle

The influence of random telegraph noise (RTN) could reduce the reading margin, which would cause computational errors in data recognition. This paper proposes a current sensor based on the principle of optical fiber interference, which can avoid the interference generated during the RTN testing process and improve the accuracy due to its passive characteristics. In this study, a hafnium oxide based memristor was fabricated, the switching voltages of Cu and TiN as the top electrodes are 0.2 V and 0.15 V, respectively. In addition, the RTN spectral density of the two device structures in LRS increases from 10−5 to 10−1 A2 Hz−1 and from 10−5 to 101 A2 Hz−1 with increasing applied voltage. While the RTN in high resistance state is independent of the applied voltage. Furthermore, based on the analysis of the experimental data, the generation mechanism of the RTN is attributed to local defects and the capture or emission of carriers by traps.

Protecting quantum correlations of negative quantum states using weak measurement under non-Markovian noise

The weak measurement (WM) and quantum measurement reversal (QMR) are crucial in protecting the collapse of quantum states. The idea of WM and QMR has recently been used to protect and enhance quantum correlations and universal quantum teleportation (UQT) protocols. Here, we study the quantum correlations, maximal fidelity, and fidelity deviation of the two-qubit negative quantum states developed using discrete Wigner functions with(without) WM and QMR. To take into account the effect of a noisy environment, we evolve the states via non-Markovian amplitude damping and random telegraph noise quantum channels. To benchmark the performance of negative quantum states, we calculate their success probability. We compare our results with the two-qubit maximally entangled Bell state. Interestingly, we observe that some negative quantum states perform better with WM and QMR than the Bell state for different cases under evolution via noisy quantum channels.

Experimental study of time-dependent dielectric degradation by means of random telegraph noise spectroscopy

Time-dependent dielectric breakdown (TDDB) is commonly used to assess dielectric failures. However, TDDB provides limited insights into the physics of dielectric degradation. In this paper, we explore the potential of random telegraph noise (RTN) spectroscopy to study the physics of dielectric breakdown. RTN is a fluctuation in the dielectric leakage current due to capture/emission of injected electrons by dielectric traps. We report an RTN study of large-area alumina (Al2O3) thin films. A stress experiment is performed on a fresh sample, where RTN is measured before, during and after stress. Important degradation signatures are identified in the RTN spectra. The degradation imposed by the applied stress is observed as a consistent transition between two distributions, where the RTN transitions from an initial pre-stress Gaussian, to a final post-stress exponential. A calculation of the noise entropy, which generally increases with growing material disorder, confirms the transition to an exponential distribution. Finally, we relate the RTN distribution parameters to the defectivity of the dielectric.

Random Telegraph Noise and Radiation Response of 80 nm Vertical Charge-Trapping NAND Flash Memory Devices with SiON Tunneling Oxide

Random Telegraph Noise and Radiation Response of 80 nm Vertical Charge-Trapping NAND Flash Memory Devices with SiON Tunneling Oxide

Analysis of Sinusoid Plus Random Telegraph Noise in Nonlinear Devices: Series Characteristic Function Method

Analysis of Sinusoid Plus Random Telegraph Noise in Nonlinear Devices: Series Characteristic Function Method

Ionizing radiation influence on 28-nm MOS transistor's low-frequency noise characteristics

In this paper, we explore the transitions of low-frequency noise characteristics in high-k metal-gate bulk CMOS transistors induced by Total Ionizing Dose (TID). Due to the strong bias dependence of the noise characteristics, differentiating between noise shifts caused by the effective biasing change and the contribution of the newly generated traps becomes extremely challenging. In order to better understand the effects of irradiation, transistor noise had to be characterized at several biasing points, both in linear and saturation regions, before and after exposure to 1 Grad (SiO2) of TID. Correlation between shifts in time and frequency domain is presented in this work, along with possible explanations for each variation that occurs. We present examples of irradiation-generated Random Telegraph Noise (RTN) defects as well as various TID effects on noise Power Spectral Density (PSD) curves with pre-existing RTN sources.

Quantum non-local correlation testing of the Werner state in non-Markovian environment

Research on whether quantum states retain quantum non-local correlation properties after evolving in non-Markovian environments has significant applications in the field of quantum information. This article presents the evolution results of the density matrix of quantum states over time in various non-Markovian environments. Specifically, we examine two types of non-Markovian phase damping environments: Random Telegraph (RT) noise and Ornstein-Uhlenbeck (OU) noise, as well as a nonMarkovian amplitude damping (AD) environment. By utilizing the Clauser-Horne-Shimony-Holt (CHSH) inequality, the quantum non-local correlation testing of the Werner state following its evolution in these nonMarkovian environments is studied. The results show significant differences in the quantum non-local correlation testing results of the Werner state after evolving in different non-Markovian environments. Notably, the Werner state displays information backflow in the RT noise environment and the AD environment, resulting in periodic oscillations in its quantum non-local correlation testing. This suggests that under certain conditions, the quantum state can transition from a state devoid of quantum non-local correlation back to a state possessing such correlation as evolution time progresses. The results also show that the Werner state exhibits information backflow phenomena in both RT noise and AD environments, leading to periodic oscillations in its quantum non-local correlation testing. Furthermore, these periods are inversely proportional to certain parameters, such as $\sqrt{\left(\frac{2 \gamma}{a}\right)^2-1}$ and $\sqrt{2 \frac{\Gamma}{\gamma}-\left(\frac{\Gamma}{\gamma}\right)^2}$. In contrast, in the OU noise environment, no information backflow is observed, leading to a decrease in the value of the quantum non-local correlation test with increasing evolution time. In most AD and OU noise environments, there exists a specific maximum evolution time $\gamma t_{\max }$ within which successful quantum non-local correlation testing can be conducted. This maximum evolution time $\gamma t_{\max }$ varies nonlinearly with increasing fidelity and inversely with increasing $\Gamma / \gamma$ parameters. In comparison, the maximum evolution time for successful quantum non-local correlation testing in the OU noise environment surpasses that in the AD environment under the same conditions, indicating that the AD environment exerts a more pronounced weakening effect on the quantum non-local correlation properties of the Werner state.

Jitter due to Random Telegraph Noise: a Study on the Time Dependent Variability of a Ring Oscillator

Random Telegraph Noise is a relevant source of variability in integrated circuits and a growing issue due to device scaling. Jitter is one of its consequences; therefore, it is an important parameter of performance measurements for electronic components and systems. In this paper, the relationship between Random Telegraph Noise and different concepts of jitter is studied. Firstly, a gate delay variability study of a CMOS inverter is discussed. Then, an absolute, a periodic, and a cycle-to-cycle jitter are evaluated in a five-stage ring oscillator. All the data were generated with a spice simulator modified to properly account for Random Telegraph Noise, using the Monte Carlo technique.

Bias dependence in statistical random telegraph noise analysis based on nanoscale CMOS ring oscillators

Random Telegraph Noise (RTN) is one of the major reliability concerns in nanoscale complementary metal-oxide semiconductor (CMOS) technologies. In this paper, we discuss the characterization of RTN in 40 nm CMOS technology using Ring Oscillators (ROSCs). We used different types of ROSCs to study the temporal and spectral characteristics of the RTN. We conducted measurements on one of the arrays with 128 identical ROSC cells. These results enabled statistical characterization of the RTN amplitude strength and its frequency characteristics in different supply voltage variations from 0.5 V to 0.7 V. At power supply of 0.65 V, dominant and observable RTN amplitude above 0.37% Δf/fmean\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Delta f/f_{\ ext{mean}}$$\\end{document} is found in 60% of cells in the array. Further, the capture and emission time constant τe//c\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ au_{e//c}$$\\end{document} can be extracted from the measurements, the values observed ranging from 0.2 μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\upmu$$\\end{document}s to 10 ms.

Effect of Nitrogen Ion Diffusion Jumps in Nanometer-Sized Si3N4 Memristors Investigated by Low-Frequency Noise Spectroscopy

The elementary jumps in the electron current through conducting filaments of two nanometer-sized virtual memristor structures consisting of a contact of a conductive atomic force microscope probe to the Si3N4 layer with the thickness of 6[Formula: see text]nm deposited onto the [Formula: see text]-Si(001) conductive substrates are investigated. These structures are: (S1) the Si3N4/Si film; (S2) the Si3N4/SiO2/Si stack, a similar structure with 2[Formula: see text]nm SiO2 sublayer between the film and the substrate. Usually, such investigations are performed by the analysis of the waveform of this current with the aim of extracting the random telegraph noise (RTN). Here, we develop a new indirect method, which is based on the measurement of the spectrum of the low-frequency flicker noise in the current without extracting the RTN. We propose that the flicker noise is caused by the motion (drift/diffusion) of nitrogen ions via vacancies within and around the filament. The number of these ions is estimated by taking into account the geometrical parameters of the filament. This allows us to estimate the root mean square magnitude [Formula: see text] of the current jumps, which are caused by random jumps of nitrogen ions, and the number M of these ions. This is fundamental for understanding the elementary mechanisms of the electron current flowing through the filament and the resistive switching in memristor devices.

Systematical Investigation of Flicker Noise in 14 nm FinFET Devices towards Stochastic Computing Application.

Stochastic computing (SC) is widely known for its high error tolerance and efficient computing ability of complex functions with remarkably simple logic gates. The noise of electronic devices is widely used to be the entropy source due to its randomness. Compared with thermal noise and random telegraph noise (RTN), flicker noise is favored by researchers because of its high noise density. Meanwhile, unlike using RRAM, PCRAM and other emerging memory devices as the entropy source, using logic devices does not require any additional process steps, which is significant for industrialization. In this work, we systematically and statistically studied the 1/f noise characteristics of 14 nm FinFET, and found that miniaturizing the channel area of the device or lowering the ambient temperature can effectively increase the 1/f noise density of the device. This is of great importance to improve the accuracy of the SC system and simplify the complexity of the stochastic number generator (SNG) circuit. At the same time, these rules of 1/f noise characteristics in FinFET devices can provide good guidance for our device selection in circuit design.

Bi2O2Se-Based Bimode Noise Generator for the Application of Generative Adversarial Networks.

In the emerging technology, the generative aversive networks (GANs), randomness, and unpredictability of inputting noises are the keys to the uniqueness, diversity, robustness, and security of the generated images. Compared with deterministic software-based noise generation, hardware-based noise generation introduces physical entropy sources, such as electronic and photonic noises, to add unpredictability. In this study, bimode Bi2O2Se-based noise generators have been demonstrated for the application of GANs. Harnessing its ultrahigh carrier mobility, excellent air stability, marvelous optoelectronic performance, as well as the unique surface resistive switching effect and defect locations in the energy diagram, Bi2O2Se provides a good material platform to easily integrate with multiple device architectures for generating noises in different physical sources. The noise of the black current mode in a photodetector architecture and the random telegraph noise in a memristor mode were measured, characterized, compared, and analyzed. A method of Markov chain equipped with K-means clustering was carried out to calculate the discrete noise states and the transition probability matrix between them. To evaluate the generated properties of the GANs based on the hardware noise source, the inception score and Fréchet inception distance were evaluated.

Low-temperature enhanced OFF-state telegraph noise in defect engineered ReRAMs

The OFF-state retention characteristics of Pt/NiOx–(Ar)/NiOx–(Ar + O2)/Pt stacking resistive random access memory structures were measured as a function of temperature between 300 and 190 K. The devices show random telegraph noise effects whose noise amplitude increases upon lowering the temperature. Interestingly, the application of forward and reverse biases produces up and downresistance jumps. These results present important insights into the thermally activated charge trapping/de-trapping phenomenon that is responsible for resistance fluctuations.