Intrinsic parameter fluctuations in decananometer MOSFETs introduced by gate line edge roughness

In this paper, we use statistical three-dimensional (3-D) simulations to study the impact of the gate line edge roughness (LER) on the intrinsic parameters fluctuations in deep decananometer (sub 50 nm) gate MOSFETs. The line edge roughness is introduced using a Fourier synthesis technique based on the power spectrum of a Gaussian autocorrelation function. In carefully designed simulation experiments, we investigate the impact of the rms amplitude /spl Delta/ and the correlation length /spl Lambda/ on the intrinsic parameter fluctuations in well scaled, but simple devices with fixed geometry as well as the channel length and width dependence of the fluctuations at fixed LER parameters. For the first time, we superimpose in the simulations LER and random discrete dopants and investigate their relative contribution to the intrinsic parameter fluctuations in the investigated devices. For particular MOSFET geometries, we were able to identify the regions where each of these two sources of intrinsic parameter fluctuations dominates

Reentrant Adhesion Behavior in Nanocluster Deposition

We simulate the collision of atomic clusters with a weakly attractive surface using molecular dynamics in a regime between soft-landing and fragmentation, where the cluster undergoes large deformation but remains intact. As a function of incident kinetic energy, we find a transition from adhesion to reflection at low kinetic energies. We also identify a second adhesive regime at intermediate kinetic energies, where strong deformation of the cluster leads to an increase in contact area and adhesive energy.Comment: 7 pages, 6 figure

Estimating healthcare demand for an aging population: a flexible and robust bayesian joint model

In this paper, we analyse two frequently used measures of the demand for health care, namely hospital visits and out-of-pocket health care expenditure, which have been analysed separately in the existing literature. Given that these two measures of healthcare demand are highly likely to be closely correlated, we propose a framework to jointly model hospital visits and out-of-pocket medical expenditure. Furthermore, the joint framework allows for the presence of non-linear effects of covariates using splines to capture the effects of aging on healthcare demand. Sample heterogeneity is modelled robustly with the random effects following Dirichlet process priors with explicit cross-part correlation. The findings of our empirical analysis of the U.S. Health and Retirement Survey indicate that the demand for healthcare varies with age and gender and exhibits significant cross-part correlation that provides a rich understanding of how aging affects health care demand, which is of particular policy relevance in the context of an aging population

Fundamental data on the desorption of pure interstellar ices

The desorption of molecular ices from grain surfaces is important in a number of astrophysical environments including dense molecular clouds, cometary nuclei and the surfaces and atmospheres of some planets. With this in mind, we have performed a detailed investigation of the desorption of pure water, pure methanol and pure ammonia ices from a model dust-grain surface. We have used these results to determine the desorption energy, order of desorption and the pre-exponential factor for the desorption of these molecular ices from our model surface. We find good agreement between our desorption energies and those determined previously; however, our values for the desorption orders, and hence also the pre-exponential factors, are different to those reported previously. The kinetic parameters derived from our data have been used to model desorption on time-scales relevant to astrophysical processes and to calculate molecular residence times, given in terms of population half-life as a function of temperature. These results show the importance of laboratory data for the understanding of astronomical situations whereby icy mantles are warmed by nearby stars and by other dynamical events

RTS amplitudes in decanano n-MOSFETs with conventional and high-k gate stacks

Low frequency (LF) noise in MOSFETs has been a topic of interest to both academia and industry in recent years. It is becoming a major concern for analogue circuit performance, DRAM operation, and will eventually impact critically upon the reliability of digital logic especially as devices continue to scale towards nano dimensions. Random telegraph signals (RTS) caused by the capture and emission of carriers in traps at the Si/SiO/sub 2/ interface have been posited as a major component of low frequency noise in semiconductor devices. The change in the drain current associated with trapping events in defect states is usually referred to as the RTS amplitude. The magnitude of the RTS amplitude is largest in the subthreshold regime at lower gate voltages and is reduced in the strong inversion regime as mobile charge in the inversion layer increasingly screens out the electrostatic influence of the trapped charge. We study the magnitude of the RTS amplitudes in nano-CMOS devices with conventional and high- gate stacks. Traps at the front and back gate dielectric interfaces, as well as traps in the body of the dielectric are considered. The impact of poly gate depletion is also taken into account

Foreground removal requirements for measuring large-scale CMB B-modes in light of BICEP2

The most convincing confirmation that the B-mode polarization signal detected at degree scales by BICEP2 is due to the Cosmic Microwave Background (CMB) would be the measurement of its large-scale counterpart. We assess the requirements for diffuse component separation accuracy over large portions of the sky in order to measure the large-scale B-mode signal corresponding to a tensor to scalar ratio of r=0.1-0.2. We use the method proposed by Bonaldi & Ricciardi (2011) to forecast the performances of different simulated experiments taking into account noise and foreground removal issues. We do not consider instrumental systematics, and we implicitly assume that they are not the dominant source of error. If this is the case, the confirmation of an r=0.1-0.2 signal is achievable by Planck even for conservative assumptions regarding the accuracy of foreground cleaning. Our forecasts suggest that the combination of this experiment with BICEP2 will lead to an improvement of 25-45% in the constraint on r. A next-generation CMB polarization satellite, represented in this work by the COrE experiment, can reduce dramatically (by almost another order of magnitude) the uncertainty on r. In this case, however, the accuracy of foreground removal becomes critical to fully benefit from the increase in sensitivity.Comment: 8 pages, 3 figures, 1 table. Accepted by MNRA

The influence of steps on the dissociation of NO on Pt surfaces: Temperature-programmed desorption studies of NO adsorption on Pt{211}

Temperature-programmed desorption (TPD) has been used to investigate the adsorption of NO on Pt{211} at 300 K and 120 K. Results show that NO dissociation occurs readily on Pt{211}, as evidenced by the observation of N-2 and N2O in the TPD spectrum. Following adsorption at 120 K three NO TPD peaks at 338, 416, and 503 K are observed, in agreement with previous observations. In combination with data acquired in a recent reflection absorption infrared spectroscopy and density functional theory investigation of NO/Pt{211}, these peaks are assigned to the desorption of NO from an O-NO complex, the recombinative desorption of N and O atoms, and to desorption of a step-bridged NO species, respectively. These assignments are in disagreement with previous work, where the high-temperature NO peak was assigned to the desorption of step bound NO and the two low-temperature peaks were assigned to the desorption of NO from terrace sites. TPD spectra recorded following adsorption at 300 K, with a heating rate of 1 K s(-1), show similar features to those recorded following 120 K adsorption. This is also in disagreement with previous observations, where only two NO TPD peaks were observed following adsorption at room temperature. This disagreement can be accounted for by the different heating rates used in the two experiments. (C) 2003 American Institute of Physics