RTS amplitudes in decananometer MOSFETs: 3-D simulation study

In this paper we study the amplitudes of random telegraph signals (RTS) associated with the trapping of a single electron in defect states at the Si/SiO/sub 2/ interface of sub-100-nm (decananometer) MOSFETs employing three-dimensional (3-D) "atomistic" simulations. Both continuous doping charge and random discrete dopants in the active region of the MOSFETs are considered in the simulations. The dependence of the RTS amplitudes on the position of the trapped charge in the channel and on device design parameters such as dimensions, oxide thickness and channel doping concentration is studied in detail. The 3-D simulations offer a natural explanation for the large variation in the RTS amplitudes measured experimentally in otherwise identical MOSFETs. The random discrete dopant simulations result in RTS amplitudes several times higher compared to continuous charge simulations. They also produce closer to the experimentally observed distributions of the RTS amplitudes. The results highlight the significant impact of single charge trapping in the next generation decananometer MOSFETs

Random telegraph signal amplitudes in sub 100 nm (decanano) MOSFETs: a 3D `Atomistic' simulation study

In this paper we use 3D simulations to study the amplitudes of random telegraph signals (RTS) associated with the trapping of a single carrier in interface states in the channel of sub 100 nm (decanano) MOSFETs. Both simulations using continuous doping charge and random discrete dopants in the active region of the MOSFETs are presented. We have studied the dependence of the RTS amplitudes on the position of the trapped charge in the channel and on the device design parameters. We have observed a significant increase in the maximum RTS amplitude when discrete random dopants are employed in the simulations

Simulation of intrinsic parameter fluctuations in decananometer and nanometer-scale MOSFETs

Intrinsic parameter fluctuations introduced by discreteness of charge and matter will play an increasingly important role when semiconductor devices are scaled to decananometer and nanometer dimensions in next-generation integrated circuits and systems. In this paper, we review the analytical and the numerical simulation techniques used to study and predict such intrinsic parameters fluctuations. We consider random discrete dopants, trapped charges, atomic-scale interface roughness, and line edge roughness as sources of intrinsic parameter fluctuations. The presented theoretical approach based on Green's functions is restricted to the case of random discrete charges. The numerical simulation approaches based on the drift diffusion approximation with density gradient quantum corrections covers all of the listed sources of fluctuations. The results show that the intrinsic fluctuations in conventional MOSFETs, and later in double gate architectures, will reach levels that will affect the yield and the functionality of the next generation analog and digital circuits unless appropriate changes to the design are made. The future challenges that have to be addressed in order to improve the accuracy and the predictive power of the intrinsic fluctuation simulations are also discussed

Demonstration of fundamental mode only propagation in highly multimode fibre for high power EDFAs

The use of short lengths of large core phosphate glass fibre, doped with high concentrations of Er or Er:Yb represents an attractive route to achieving high power erbium doped fibre amplifiers (EDFAs) and lasers (EDFLs). With the aim of investigating the potential of achieving diffraction limited output from such large core fibres, we present experimental results of fundamental mode propagation through a 20 cm length of passive 300 micrometer core multimode fibre when the input is a well-aligned Gaussian beam. Through careful control of fibre geometry, input beam parameters and alignment, we measured an output M squared of 1.1 + - 0.05. The fibre had a numerical aperture of 0.389, implying a V number of 236.8. To our knowledge, this is the largest core fibre through which diffraction limited fundamental mode propagation has been demonstrated. Although the results presented here relate to undoped fibre, they do provide the practical basis for a new generation of EDFAs and EDFLs.Comment: 5 figure

Deep Chandra Monitoring Observations of NGC 4278 : Catalog of Source Properties

We present the properties of the discrete X-ray sources detected in our monitoring program of the globular cluster (GC) rich elliptical galaxy, NGC 4278, observed with Chandra ACIS-S in six separate pointings, resulting in a co-added exposure of 458 ks. From this deep observation, 236 sources have been detected within the region overlapped by all observations, 180 of which lie within the D 25 ellipse of the galaxy. These 236 sources range in L X from 3.5 × 1036 erg s-1 (with 3σ upper limit 1 × 1038 erg s-1. From X-ray source photometry, it has been determined that the majority of the 236 point sources that have well-constrained colors have values that are consistent with typical low-mass X-ray binary spectra, with 29 of these sources expected to be background objects from the log N-log S relation. There are 103 sources in this population that exhibit long-term variability, indicating that they are accreting compact objects. Three of these sources have been identified as transient candidates, with a further three possible transients. Spectral variations have also been identified in the majority of the source population, where a diverse range of variability has been identified, indicating that there are many different source classes located within this galaxy.Peer reviewe

Determinant Representations for Correlation Functions of Spin-1/2 XXX and XXZ Heisenberg Magnets

We consider correlation functions of the spin-\half XXX and XXZ Heisenberg chains in a magnetic field. Starting from the algebraic Bethe Ansatz we derive representations for various correlation functions in terms of determinants of Fredholm integral operators.Comment: 23 pages, TeX, BONN-TH-94-14, revised version: typos correcte

Editorial: Is there a new climate politics?

Addressing climate change globally requires significant transformations of production and consumption systems. The language around climate action has shifted tangibly over the last five years to reflect this. Indeed, thousands of local governments, national governments, universities and scientists have declared a climate emergency. Some commentators argue that the emergency framing conveys a new and more appropriate level of urgency needed to respond to climate challenges; to create a social tipping point in the fight against climate change. Others are concerned to move on from such emergency rhetoric to urgent action. Beyond emergency declarations, new spaces of, and places for, engagement with climate change are emerging. The public square, the exhibition hall, the law courts, and the investors’ forum are just some of the arenas where climate change politics are now being negotiated. Emergent governing mechanisms are being utilised, from citizens’ assemblies to ecocide lawsuits. New social movements from Extinction Rebellion to Fridays For Future demonstrate heightened concern and willingness to undertake civil disobedience and protest against climate inaction. Yet questions remain which are addressed in this thematic issue: Are these discourses and spaces of engagement manifestations of a radical new climate politics? And if these are new climate politics, do they mark a shift of gear in current discourses with the potential to effect transformative climate action and support a just transition to a decarbonised world

Perceptions of alcohol health warning labels in a large international cross-sectional survey of people who drink alcohol

Aims This paper aimed to explore perceptions of alcohol health warning labels amongst a large international sample of people who drink alcohol. Methods The Global Drug Survey (GDS) is the world’s largest annual cross sectional survey of drug use. Seven health warning labels were presented (relating to heart disease, liver, cancer, calories, violence, taking two days off and the myth of benefits to moderate drinking). People were asked if they were aware of the information, believed it, if it was personally relevant, and if it would change their drinking. This paper included data from 75,969 respondents from 29 countries/regions who reported the use of alcohol in the last 12 months, collected during November–December 2017 (GDS2018). Results The fact that drinking less can reduce the risk of seven types of cancer was the least well known, and yet was demonstrated to encourage almost 40% of drinkers to consider drinking less. Women and high risk drinkers were more likely to indicate they would reduce their drinking in response to all labels. Personal relevance was identified as a key predictor of individual responses. Conclusion Findings highlight the potential of a range of health messages displayed on alcoholic beverages to raise awareness of alcohol-related harms and potentially support a reduction in drinking. Further research should explore what influences personal relevance of messages as this may be a barrier to effectiveness