ESD protection for thin gate oxides in 65 nm

Unexpected functional failures were found in the core of an IC, processed in a 65 nm technology with 1.8 nm gate oxide, after Machine Model (MM) testing, although a comprehensive rail-based protection scheme was applied. Failure analysis was performed including Obirch, backside de-processing, and SEM analysis to locate the failure in the gate oxide of several core NMOS transistors. Careful Transmission Line Pulse (TLP) measurements on NMOSTs with 1.8 nm oxides yields a mean BVox = 6.06 V and standard deviation of 0.18 V, after correction for MM test conditions. Comparison with a mean Vt1 = 5.35 V and a standard deviation of 0.15 V for ggNMOSTs shows that the tails of the BVox and Vt1 distributions overlap. This implies that connecting a gate to a drain diffusion does not guarantee adequate protection for a 1.8 nm gate oxide in a 65 nm technology.     

Edge-based color constancy.

Color constancy is the ability to measure colors of objects independent of the color of the light source. A well-known color constancy method is based on the gray-world assumption which assumes that the average reflectance of surfaces in the world is achromatic. In this paper, we propose a new hypothesis for color constancy namely the gray-edge hypothesis, which assumes that the average edge difference in a scene is achromatic. Based on this hypothesis, we propose an algorithm for color constancy. Contrary to existing color constancy algorithms, which are computed from the zero-order structure of images, our method is based on the derivative structure of images. Furthermore, we propose a framework which unifies a variety of known (gray-world, max-RGB, Minkowski norm) and the newly proposed gray-edge and higher order gray-edge algorithms. The quality of the various instantiations of the framework is tested and compared to the state-of-the-art color constancy methods on two large data sets of images recording objects under a large number of different light sources. The experiments show that the proposed color constancy algorithms obtain comparable results as the state-of-the-art color constancy methods with the merit of being computationally more efficient.     

The challenge of general machine vision

I argue that in spite of the progress in several machine vision applications, the general machine vision problem is not going to be solved any time soon. There are three reasons for that: (1) The complexity of human vision: Bottom-up and top-down processes are tightly interwoven, and we have no good models for dealing with that; (2) The fact that perceptual similarity is not the same as mathematical similarity; (3) The illusion of progress by relying on “proofs by example” that are not always valid. I discuss several examples of applications that were successful because they did not face any of the three obstacles.     

Image formation and tomogram reconstruction in optical coherence microscopy

In this work we present a model for image formation in optical coherence microscopy. In the spectral domain detection, each wavenumber has a specific coherent transfer function that samples a different part of the object's spatial frequency spectrum. The reconstruction of the tomogram is usually accurate only in a short depth of field. Using numerical simulations based on the developed model, we identified two distinct mechanisms that influence the signal of out-of-focus sample information. Besides the lateral blurring induced through defocusing, an additional axial envelope contributing equally to the signal degradation was found.     

Linear patterning of mesenchymal condensations is modulated by geometric constraints

The development of the vertebral column starts with the formation of a linear array of mesenchymal condensations, forming the blueprint for the eventual alternating pattern of bone and cartilage. Despite growing insight into the molecular mechanisms of morphogenesis, the impact of the physical aspects of the environment is not well understood. We hypothesized that geometric boundary conditions may play a pivotal role in the linear patterning of condensations, as neighbouring tissues provide physical constraints to the cell population. To study the process of condensation and the patterning thereof under tightly controlled geometric constraints, we developed a novel in vitro model that combines micropatterning with the established micromass assay. The spacing and alignment of condensations changed with the width of the cell adhesive patterns, a phenomenon that could not be explained by cell availability alone. Moreover, the extent of chondrogenic commitment was increased on substrates with tighter geometric constraints. When the in vivo pattern of condensations was investigated in the developing vertebral column of chicken embryos, the measurements closely fit into the quantitative relation between geometric constraints and inter-condensation distance found in vitro. Together, these findings suggest a potential role of geometric constraints in skeletal patterning in a cellular process of self-organization.     

A Comparison of Finite Element and Integral Equation Formulations for the Calculation of Electrocardiographic Potentials

This paper is a comparison of the major methodologies utilized in computer simulations of electrocardiographic potential calculations. Two integral equation methods (Green's theorem and the equivalent single layer) and finite element methods are compared for forward and inverse solutions. The results suggest that the differences in accuracy between the two integral equation formulations are small. However, the use of a basic finite element formulation improves the accuracy over that obtainable with integral equations, and the improvement in accuracy is particularly notable for inverse estimation.     

The Use of Atomic Force Microscopy to Study Crack Tips in Glass

This article presents a review of the application of atomic force microscopy (AFM) to crack-tip corrosion during subcritical crack growth in glass. The two principal experimental techniques used in this type of study are (1) the direct observation of crack motion by scanning the tip of a crack during crack growth and (2) the examination of fracture surfaces once the specimen has been fractured in two. The first technique has been used to demonstrate and quantify water condensation at crack tips during subcritical crack growth and is particularly useful at low crack velocities. The second technique has been used to quantify the crack-tip corrosion process and the shape of the crack tip during crack growth. In this article, we discuss experimental results showing that the environment that develops at the tips of freshly fractured glass surfaces in soda lime glass can corrode the glass surfaces near the crack tip. Soda lime silicate glass contains mobile alkali ions that will exchange with hydronium ions in solution at the crack tip, forming a highly basic solution that is corrosive to glass. Experimental evidence for such corrosion has been obtained by the atomic force microscope, which demonstrates a displacement of the two fracture surfaces near the crack tip that can be as much as 20 nm, depending on how long the crack is held open at the fatigue limit. Despite the corrosion and displacement of the crack surfaces, the crack tip itself appears to remain sharp, suggesting that the fatigue limit in soda lime silicate glass is not due to crack-tip blunting. Most likely, the fatigue limit is a consequence of ion exchange at the crack tip, in which hydronium ions in the crack-tip solution exchange with sodium ions in the glass. As hydronium ions are larger than sodium ions, this exchange process leaves a compressive stress within the fresh fracture surface of the glass that resists crack motion and results in a stress-corrosion fatigue limit, as first proposed by Bunker and Michalske. In agreement with this mechanism, no fatigue limit is observed for silica glass, which also exhibits no ion exchange. As the crack-tip solution in silica glass is only mildly acidic, pH ≈ 5, corrosion does not occur at crack tips of this glass as supported by the observation that no crack-tip displacements are observed in silica glass by AFM. As the proposed ion exchange mechanism used to explain the stress corrosion limit in glass is at variance with the belief that the fatigue limit in glass is the result of crack-tip blunting, we discuss the possibility of plastic deformation at crack tips in glass and conclude that the available experimental data does not support such a model. At the present time, chemical reaction based crack growth theories are most consistent with the body of crack growth data that is available on glass and are probably the best explanation for the phenomenon.     

Relations between the Pleasant Events Schedule, depression, and other aspects of psychopathology.

Studied the relations between the Mood Related subscale of the Pleasant Events Schedule (PES), depression, and other psychopathology. 100 psychiatric inpatients and outpatients (mean age 35.7 yrs) had diagnoses of either major, nonmajor, or no depression. All Ss completed the PES, the Beck Depression Inventory, the State-Trait Anxiety Inventory, and a Dutch personality questionnaire. Results show that the PES correlated negatively with depression as well as with anxiety and (social) neuroticism. Principal components analysis revealed 2 factors, negative and positive affect. The latter was dominated by PES scores. Using factor scores, the 3 diagnostic groups could be meaningfully discriminated. It is concluded that depression may be better described using 2 affect dimensions rather than 1. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)