Investigation of the RTN Distribution of nanoscale MOS devices from subthreshold to on-state

This letter presents a numerical investigation of the statistical distribution of the random telegraph noise (RTN) amplitude in nanoscale MOS devices, focusing on the change of its main features when moving from the subthreshold to the on-state conduction regime. Results show that while the distribution can be well approximated by an exponential behavior in subthreshold, large deviations from this behavior appear when moving toward the on-state regime, despite a low probability exponential tail at high RTN amplitudes being preserved. The average value of the distribution is shown to keep an inverse proportionality to channel area, while the slope of the high-amplitude exponential tail changes its dependence on device width, length, and doping when moving from subthreshold to on-state

Insight into Electron Traps and Their Energy Distribution under Positive Bias Temperature Stress and Hot Carrier Aging

The access transistor of SRAM can suffer both Positive Bias Temperature Instability (PBTI) and Hot Carrier Aging (HCA) during operation. The understanding of electron traps (ETs) is still incomplete and there is little information on their similarity and differences under these two stress modes. The key objective of this paper is to investigate ETs in terms of energy distribution, charging and discharging properties, and generation. We found that both PBTI and HCA can charge ETs which center at 1.4eV below conduction band (Ec) of high-k (HK) dielectric, agreeing with theoretical calculation. For the first time, clear evidences are presented that HCA generates new ETs, which do not exist when stressed by PBTI. When charged, the generated ETs’ peak is 0.2eV deeper than that of pre-existing ETs. In contrast with the power law kinetics for charging the pre-existing ETs, filling the generated ETs saturates in seconds, even under an operation bias of 0.9 V. ET generation shortens device lifetime and must be included in modelling HCA. A cyclic and anti-neutralization ETs model (CAM) is proposed to explain PBTI and HCA degradation, which consists of pre-existing cyclic electron traps (PCET), generated cyclic electron traps (GCET), and anti-neutralization electron traps (ANET)

Hot carrier aging and its variation under use-bias: kinetics, prediction, impact on Vdd and SRAM

As CMOS scales down, hot carrier aging (HCA) scales up and can be a limiting aging process again. This has motivated re-visiting HCA, but recent works have focused on accelerated HCA by raising stress biases and there is little information on HCA under use-biases. Early works proposed that HCA mechanism under high and low biases are different, questioning if the high-bias data can be used for predicting HCA under use-bias. A key advance of this work is proposing a new methodology for evaluating the HCA-induced variation under use-bias. For the first time, the capability of predicting HCA under use-bias is experimentally verified. The importance of separating RTN from HCA is demonstrated. We point out the HCA measured by the commercial Source-Measure-Unit (SMU) gives erroneous power exponent. The proposed methodology minimizes the number of tests and the model requires only 3 fitting parameters, making it readily implementable

Oxide Soft BreakDown : From Device Modeling to Small Circuit Simulation

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RTN distribution comparison for bulk, FDSOI and FinFETs devices

In this paper we investigate the sensitivity of RTN noise spectra to statistical variability alone and in combination with variability in the traps properties, such as trap level and trap activation energy. By means of 3D statistical simulation, we demonstrate the latter to be mostly responsible for noise density spectra dispersion, due to its large impact on the RTN characteristic time. As a result FinFETs devices are shown to be slightly more sensitive to RTN than FDSOI devices. In comparison bulk MOSFETs are strongly disadvantaged by the statistical variability associated with high channel doping

Impact of Oxide Progressive Soft Breakdown: Experiment and Modeling.

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Impact of Progressive Soft Oxide Breakdown on MOS Parameters: Experiment and Modelling.

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Comprehensive 'Atomistic' Simulation of Statistical Variability and Reliability in 14 nm Generation FinFETs

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Unified Soft Breakdown MOSFETs Compact Model: From Experiments to Circuit Simulation

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