Non-Markovianity is not a resource for quantum spatial search on a star graph subject to generalized percolation

In this paper, we analyze the effects of single-chargetrapinduced random telegraphic noise (RTN) on asymmetricdual high-K spacer based FinFET (ADS-FinFET). The effectsof RTN reduces in proposed device because asymmetric high-K spacer reduces the electric field effect at source and formation of the barrier between source to gate/drain. The spacer width optimization will provide maximum possible performance and tolerant towards RTN at 12 nm high-K spacer width. Reduced equivalent oxide thickness (EOT) also help to reduce RTN effect whereas, RTN impact increases with device scaling.

An observation on random telegraph noise (RTN) signal in the read current of a FinFET Dielectric RRAM (FIND RRAM) device is presented in this work. The RTN signal of a FIND RRAM cell is found to change with stress and ambient temperature. Cells with more cycling stress show a stronger tendency to exhibit RTN signals. RTN signals in FIND cells can be generally alleviated by high temperature anneal, and an on chip annealing scheme is proposed and demonstrated.

In this paper, based on the complex random telegraph noise (RTN) data in FinFETs, the impacts of the trap coupling effect on RTN amplitude are studied statistically. The coupling effect is found to be enhanced by the double-side coupling mechanism in FinFETs. The non-monotonic V g dependence of amplitude coupling strength is observed for the first time, which is contributed by the evolution of channel percolation paths. In addition, the impacts of HCI and NBTI stresses on the coupling strength are studied. Based on the new understandings on coupling effect in FinFETs, the impacts of amplitude coupling on typical digital circuits are also investigated. The results are helpful for comprehensive understanding of the RTN coupling mechanism in nanoscale FinFET technology and RTN-aware circuit design.

This paper investigates the main features of the random telegraph noise statistical instability in Flash memory arrays. The exponential tails introduced in the cumulative distribution of the threshold voltage variation between two subsequent read operations on the cells are shown to be preserved when the available statistics is increased. Large threshold voltage instabilities are therefore to be admitted, requiring the possibility for large random telegraph noise fluctuation amplitudes and the superposition of multi-trap random telegraph noise effects. Moreover, tails drift for increasing elapsed time between the compared read operations due to the activation of slower and slower traps in the random telegraph noise process, whose effect should be carefully considered in drawing reliability projections. Finally, the results for an early and an optimized NOR process are presented, showing non-negligible differences in their exponential tails behavior and revealing the existence of important parameters other than the technology node feature size having a significant impact on the random telegraph noise instability.

We address quantum spatial search on graphs and its implementation by continuous-time quantum walks in the presence of dynamical noise. In particular, we focus on search on the complete graph and on the star graph of order $N$, proving that also the latter is optimal in the computational limit $N \gg 1$, being nearly optimal also for small $N$. The noise is modeled by independent sources of random telegraph noise (RTN), dynamically perturbing the links of the graph. We observe two different behaviours depending on the switching rate of RTN: fast noise only slightly degrades performance, whereas slow noise is more detrimental and, in general, lowers the success probability. In particular, we still find a quadratic speed-up for the average running time of the algorithm, while for the star graph with external target node we observe a transition to classical scaling. We also address how the effects of noise depend on the order of the graphs, and discuss the role of the graph topology. Overall, our results suggest that realizations of quantum spatial search are possible with current technology, and also indicate the star graph as the perfect candidate for the implementation by noisy quantum walks, owing to its simple topology and nearly optimal performance also for just few nodes.

A system of three non-interacting qubits is used as a quantum probe to classify three classical non-Gaussian noises namely, the static noise (SN), colored noise (pink and brown spectrum) and random telegraph noise (RTN), according to their detrimental effects on the evolution of entanglement of the latter. The probe system is initially prepared in the GHZ state and coupled to the noises in independent environments. Seven configurations for the qubit-noise coupling (QNC) are considered. To estimate the destructive influence of each kind of noise, the tripartite negativity is employed to compare the evolution of entanglement in these QNC configurations to each other with the same noise parameters. It is shown that the evolution of entanglement is drastically impacted by the QNC configuration considered as well as the properties of the environmental noises and that the SN is more detrimental to the survival of entanglement than the RTN and colored noise, regardless of the Markov or non-Markov character of the RTN and the spectrum of the colored noise. On the other hand, it is shown that pink noise is more fatal to the system than the RTN and that the situation is totally reversed in the case of brown noise. Finally, it is demonstrated that these noises, in descending order of destructive influence, can be classified as follows: SN > pink noise > RTN > brown noise.

In this paper, multi-phonon transition model of RTN in FinFETs with statistical distribution is integrated into industry-standard BSIM-CMG, and read stability of SRAM is thoroughly examined. Different tendencies of SRAM failure probability plateau caused by RTN are found, which reflect real circuit operation situations. The impacts of RTN amplitude, bitline capacity, operation frequency on Vmin are investigated in detail. Statistical results with impacts of RTN and process variations are also presented, which can be helpful for stability design and guard band prediction for SRAM.

Random Telegraph Noise (RTN) effects are investigated in 65nm SRAM cells by using a new characterization method that provides a significant measurement time reduction. The variability induced in commercial SRAM cells is derived by applying statistical and physics based Montecarlo modeling to the experimental data. Results show that RTN can have a significant impact on the memory write operations and should therefore be taken into account during the memory design phase.

The effect of random telegraph noise (RTN) on write stability of SRAM cells in sub-0.4V operation is intensively measured and statistically analyzed. RTN of N-curves in Silicon-on-Thin-BOX (SOTB) cells is monitored. By developing statistical models, it is found that, different from bulk SRAM cells operating at high supply voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DD</sub> ), fail bit rate (FBR) at sub-0.4V is degraded by RTN. The origin of high FBR due to RTN at sub-0.4V is discussed.

We investigate the dynamics of entanglement, quantum discord (QD) and state coherence in a bipartite and noninteracting spin-qutrits system under mixed classical noises. Specifically, the collective effects of static noise (SN) and random telegraphic noise (RTN) each being coupled with a marginal system, are analyzed. While the static noise models a non-Markovian environment, the dynamic noise can model both a Markovian or a non-Markovian environment, and both dynamics are studied. We show that quantum correlations and coherence may survive the noise degrading effects at sufficiently long time when the Markovian regime of the RTN is considered. Meanwhile, the opposite is found in the non-Markovian regime, wherein the nonmonotonic dynamics of quantum features avoid sudden death phenomena. However, the static noise is more fatal to the survival of quantum correlations and quantum state coherence as compared to the RTN.

Comprehensive physics-based RRAM compact model including the effect of variability and multi-level random telegraph noise

NAND flash memory has been dominantly used in consumer electronic products ranging from hand-held phones to personal computers. However, the stored data in NAND flash memory is subject to several impairments such as Random Telegraph Noise (RTN), Cell-to-Cell Interference (CCI) and Data Retention Effect over time. In this paper, we focus on the RTN effect over flash memory cells which becomes even more serious as the memory approaches its lifetime. When the flash cells withstand increasingly large number of Program/Erase (P/E) operation, multiple interface traps are generated at tunnel oxide layer which results into large fluctuations in cell threshold voltage. These voltage fluctuations, in turn, degrade the system error performance. To tackle with this problem, we propose a simple yet effective system-level decoding scheme in which the memory cells are read multiple times to obtain threshold voltage fluctuations caused by RTN. Since each memory read operation produces a new realization of threshold voltage, we combine the read signal with LDPC extrinsic information. The performance improvements of our scheme are validated by computer simulation which shows that the lifetime of flash memory can be extended by more than 10K P/E cycles while maintaining bit-error-rate at 10−6 using NB-LDPC code over GF (4) with frame size N = 2272. This paper also presents the trade-off between performance improvement and extra memory sensing latency.

One of the emerging challenges in the scaling of MOSFETs is the reliability of ultra-thin gate dielectrics. Various sources can cause device aging, such as hot carrier aging (HCA), negative bias temperature instability (NBTI), positive bias temperature instability (PBTI), and time dependent device breakdown (TDDB). Among them, hot carrier aging (HCA) has attracted much attention recently, because it is limiting the device lifetime. As the channel length of MOSFETs becomes smaller, the lateral electrical field increases and charge carriers become sufficiently energetic (“hot”) to cause damage to the device when they travel through the space charge region near the drain. Unlike aging that causes device parameters, such as threshold voltage, to drift in one direction, nano-scale devices also suffer from Random Telegraph Noise (RTN), where the current can fluctuate under fixed biases. RTN is caused by capturing/emitting charge carriers from/to the conduction channel. As the device sizes are reduced to the nano-meters, a single trap can cause substantial fluctuation in the current and threshold voltage. Although early works on HCA and RTN have improved the understanding, many issues remain unresolved and the aim of this project is to address these issues. The project is broadly divided into three parts: (i) an investigation on the HCA kinetics and how to predict HCA-induced device lifetime, (ii) a study of the interaction between HCA and RTN, and (iii) developing a new technique for directly measuring the RTN-induced jitter in the threshold voltage. To predict the device lifetime, a reliable aging kinetics is indispensable. Although early works show that HCA follows a power law, there are uncertainties in the extraction of the time exponent, making the prediction doubtful. A systematic experimental investigation was carried out in Chapter 4 and both the stress conditions and measurement parameters were carefully selected. It was found that the forward saturation current, commonly used in early work for monitoring HCA, leads to an overestimation of time exponents, because part of the damaged region is screened off by the space charges near the drain. Another source of errors comes from the inclusion of as-grown defects in the aging kinetics, which is not caused by aging. This leads to an underestimation of the time exponent. After correcting these errors, a reliable HCA kinetics is established and its predictive capability is demonstrated. There is confusion on how HCA and RTN interact and this is researched into in Chapter 5. The results show that for a device of average RTN, HCA only has a modest impact on RTN. RTN can either increase or decrease after HCA, depending on whether the local current under the RTN traps is rising or reducing. For a device of abnormally high RTN, RTN reduces substantially after HCA and the mechanism for this reduction is explored. The RTN-induced threshold voltage jitter, ∆Vth, is difficult to measure, as it is typically small and highly dynamic. Early works estimate this ∆Vth from the change in drain current and the accuracy of this estimation is not known. Chapter 6 focuses on developing a new ‘Trigger-When-Charged’ technique for directly measuring the RTN-induced ∆Vth. It will be shown that early works overestimate ∆Vth by a factor of two and the origin of this overestimation is investigated. This thesis consists of seven chapters. Chapter 1 introduces the project and its objectives. A literature review is given in Chapter 2. Chapter 3 covers the test facilities, measurement techniques, and devices used in this project. The main experimental results and analysis are given in Chapters 4-6, as described above. Finally, Chapter 7 concludes the project and discusses future works.

In this paper, we develop a RRAM compact model accounting for random telegraph noise (RTN) effect. In particular, we develop a Monte Carlo method to effectively capture the behaviors of the traps in the tunneling gap, which can be used to predict the current fluctuation caused by RTN. The model is validated with experimental data under various operating conditions. The model can be applied to study RRAM circuit reliability for efficient design space explorations.

We investigate the effect of a single charge trap random telegraph noise (RTN)-induced degradation in III-V heterojunction tunnel FET (HTFET)-based SRAM. Our analysis focuses on Schmitt trigger (ST) mechanism-based variation tolerant ten-transistor SRAM. We compare iso-area SRAM cell configurations in Si-FinFET and HTFET. Our results show that HTFET ST SRAMs provide significant energy/performance enhancements even in the presence of RTN. For sub-0.2 V operation (Vcc), HTFET ST SRAM offers 15% improvement in read-write noise margins along with better variation immunity from RTN over Si-FinFET ST SRAM. A comparison with iso-area 6T Si-FinFET SRAM with wider size transistors shows 43% improved read noise margin in 10T HTFET ST SRAM at Vcc=0.175 V. In addition, HTFET ST SRAM exhibits 48X lower read access delay and 1.5X reduced power consumption over Si-FinFET ST SRAM operating at their respective Vcc-min.