4,597 research outputs found
The texture of thin NiSi films and its effect on agglomeration
Nickel silicide films are used as contacting materials in the micro electronics industry. It was recently [1] discovered that these films exhibit a peculiar type of texture, which was called 'axiotaxy', whereby certain lattice planes in the NiSi grains are preferentially aligned to (110)-type lattice planes in the single crystal Si substrate. In this contribution, we present a quantitative study of this phenomenon, using both XRD pole figure measurements and EBSD. Furthermore, we report a correlation between the texture of these NiSi films and their morphological stability during annealing at high temperature.
In spite of the small grain size in these films, EBSD could be used to determine the volume fractions of the various texture components. This provided quantitative support for the claim that axiotaxy is the main texture component in these films, as about 40% of the grains belong to one of the axiotaxial texture components, and the remaining fraction exhibits a random orientation. A discussion of the techniques used during the measurement and analysis of the EBSD data is presented, as this must be given special consideration in view of the peculiar type of texture encountered in these films.
Secondly, both XRD and EBSD were performed after annealing the NiSi films at various temperatures and durations. It is known that thin NiSi films have a strong tendency to agglomerate [2]. Our data indicates a correlation between the texture evolution and the agglomeration of the NiSi layer. Grains with axiotaxial orientation were observed to grow and thicken during the annealing process, by consuming neighboring randomly oriented grains. This suggests that the texture of the NiSi layer is a determining factor for the morphological stability of the film. The fact that grains with axiotaxial orientation grow during heat treatment can be related to the one dimensional periodicity at the interface, which lowers the interface energy and thus provides a driving force for the preferred growth of these grains. The agglomeration of NiSi films results in a significant increase of the sheet resistance. Therefore, these results illustrate the importance of texture control for the application of these films as contacts in micro-electronic devices
Upper limit to in scalar-tensor gravity theories
In a previous paper (Serna & Alimi 1996), we have pointed out the existence
of some particular scalar-tensor gravity theories able to relax the
nucleosynthesis constraint on the cosmic baryonic density. In this paper, we
present an exhaustive study of primordial nucleosynthesis in the framework of
such theories taking into account the currently adopted observational
constraints. We show that a wide class of them allows for a baryonic density
very close to that needed for the universe closure. This class of theories
converges soon enough towards General Relativity and, hence, is compatible with
all solar-system and binary pulsar gravitational tests. In other words, we show
that primordial nucleosynthesis does not always impose a very stringent bound
on the baryon contribution to the density parameter.Comment: uuencoded tar-file containing 16 pages, latex with 5 figures,
accepted for publication in Astrophysical Journal (Part 1
Influence of alloying elements on the phase formation of ultrathin Ni (<10nm) on Si(001) substrates
The influence of Ni thickness on the formation of Nickel silicides was systematically investigated between 0 and 15nm. Annealing thickness gradients distinguishes films that agglomerate (>5nm) and films that are morphologically stable (<5nm). Alloying the initial Ni layer influences this critical thickness to higher (Al, Co) and lower (Ge, Pd, Pt) values. Pole figures and in situ XRD provides information to understand this observed shift in critical thickness
Bacterial Foodborne Disease: Medical Costs and Productivity Losses
Microbial pathogens in food cause an estimated 6.5-33 million cases of human illness and up to 9,000 deaths in the United States each year. Over 40 different foodborne microbial pathogens, including fungi, viruses, parasites, and bacteria, are believed to cause human illnesses. For six bacterial pathogens, the costs of human illness are estimated to be 12.9 billion annually. Of these costs, 6.7 billion are attributed to foodborne bacteria. These estimates were developed to provide analytical support for USDA's Hazard Analysis and Critical Control Point (HACCP) systems rule for meat and poultry. (Note that the parasite Toxoplasma gondii is not included in this report.) To estimate medical costs and productivity losses, ERS uses four severity categories for acute illnesses: those who did not visit a physician, visited a physician, were hospitalized, or died prematurely. The lifetime consequences of chronic disease are included in the cost estimates for E. coli O157:H7 and fetal listeriosis.cost-of-illness, foodborne pathogens, lost productivity, medical costs, Food Consumption/Nutrition/Food Safety, Health Economics and Policy,
Economic Assessment of Food Safety Regulations: The New Approach to Meat and Poultry Inspection
USDA is now requiring all Federally inspected meat and poultry processing and slaughter plants to implement a new system called Hazard Analysis and Critical Control Points (HACCP) to reduce potentially harmful microbial pathogens in the food supply. This report finds that the benefits of the new regulations, which are the medical costs and productivity losses that are prevented when foodborne illnesses are averted, will likely exceed the costs, which include spending by firms on sanitation, temperature control, planning and training, and testing. Other, nonregulatory approaches can also improve food safety, such as providing market incentives for pathogen reduction, irradiation, and education and labeling to promote safe food handling and thorough cooking.food safety, foodborne illness, microbial pathogens, meat and poultry inspection, HACCP, cost of illness, consumer education, irradiation, Food Consumption/Nutrition/Food Safety, Livestock Production/Industries,
Providing legal services to rural and regional small business : gaps and opportunities
This article examines the findings from a survey of 207 regional small businesses and 68 regional lawyers that explored the small business experience of accessing legal services in rural and regional Victoria. In particular, it considers small business expectations of local legal practices, their degree of satisfaction with existing legal services and identifies current and potential demand and supply gaps. By doing so it seeks to determine potential areas in which regional law firms can improve, expand and refine their services in response to the current and emerging demands on them and the communities they serve.<br /
The M-type stars
The papers in this volume cover the following topics: (1) basic properties and photometric variability of M and related stars; (2) spectroscopy and nonthermal processes; (3) circumstellar radio molecular lines; (4) circumstellar shells, the formation of grains, and radiation transfer; (5) mass loss; (6) circumstellar chemistry; (7) thermal atmospheric models; (8) quasi-thermal models; (9) observations on the atmospheres of M dwarfs; and (1) theoretical work on M dwarfs
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