1,419 research outputs found
Exploratory study on microanalysis of thin films by backscattering techniques
Solid phase epitaxial growth of Si layers was studied by backscattering spectrometry for controllable electrical characteristics. Samples were fabricated by vacuum deposition on a thin layer of Sb before deposition of the amorphous Si layer. Analysis of the resulting SPEG layer showed that Sb was present in the SPEG layer of Si. The characteristic of the SPEG layer against the Si substrate was rectifying. A scanning microprobe picture of a cleaved sample established the presence of a depletion region more than 1 micron below the surface. Hall effect data indicated that the SPEG layer was n-type, with average free carrier concentration of about 10 to the 19th power cm/3 and average electron mobility of about 40 sq cm/Vs. SPEG with Pd silicide or Ni silicide transport layers showed fast initial transient growth regimes with slower growth in the steady state regimes
Des infirmieĢres praticiennes chez les meĢdecins de famille ? Perception des enjeux et perspectives
Face aux deĢfis que nous pose l'augmentation des maladies chroniques et des couĢts de la santeĢ, de nouveaux concepts de prise en charge se deĢveloppent dans les diffeĢrents pays.
Le modeĢle anglais, aĢ l'instar d'autres pays anglo-saxons, consiste aĢ confier une partie de la prise en charge des patients au cabinet du meĢdecin de famille3, aĢ des Ā« nurses practioners Ā» ou infirmieĢres4 praticiennes speĢcialiseĢes (IPS) en francĢ§ais. Ces infirmieĢres sont compeĢtentes pour traiter certaines pathologies. Pour ce faire, elles ont le droit de demander des examens meĢdicaux, d'en interpreĢter les reĢsultats et de prescrire un certain nombre de meĢdicaments.
Comment est percĢ§ue la collaboration eĢventuelle avec une IPS dans un cabinet de meĢdecine de famille par les diffeĢrents professionnels de la santeĢ en Suisse Romande ?
Ce travail se propose de reĢcolter l'avis de meĢdecins de famille ainsi que d'infirmieĢres aĢ travers des entretiens individuels. Le but est de recenser les principaux points de discussion souleveĢs par une implantation eĢventuelle de ce modeĢle en Suisse Romande.
En effet, cette pratique est nouvelle en Europe continentale ouĢ seuls quelques pays permettent actuellement aux infirmieĢres d'effectuer certaines taĢches normalement deĢvolues aux meĢdecins (1). NeĢanmoins, ce modeĢle rencontre un inteĢreĢt grandissant aupreĢs des gouvernements occidentaux et notamment helveĢtique, et est de plus en plus discuteĢ dans la litteĢrature meĢdicale.
Dans ce contexte, il est inteĢressant de connaiĢtre l'avis des professionnels de la santeĢ qui seront directement toucheĢs par une eĢventuelle implantation de ce modeĢle, aĢ savoir ici les meĢdecins de famille (MF) et les infirmieĢres.
Ce travail s'articule en trois points.
Le premier chapitre brosse la situation sanitaire mondiale puis suisse permettant de comprendre les deĢfis preĢsenteĢs aĢ notre systeĢme de santeĢ. Le modeĢle des IPS qui est une reĢponse aĢ ces deĢfis y est deĢtailleĢ.
La meĢthode et les reĢsultats des diffeĢrents entretiens explorant l'avis des participants quant au modeĢle des IPS sont exposeĢs en theĢme
Une discussion finale se propose de retenir les points importants lieĢs aĢ une eĢventuellement implantation des IPS dans les soins primaires en Suisse Romande
Space charge effects in current transport Quarterly status report
Space charge limitations of currents for use in dosimeter
Kinetics of silicide formation by thin films of V on Si and SiO_2 substrates
The reaction rate of vacuumāevaporated films of V of the order of 1000 Ć
thick is investigated by MeV He backscattering spectrometry. On substrates of singleācrystal Si and for anneal times up to several hours in the temperature range 570ā650Ā°C, VSi_2 is formed at a linear rate in time. The activation energy of the process is 1.7Ā±0.2 eV. The presence of oxygen in amounts of 10% can significantly decelerate the reaction. On substrates of SiO_2 in the temperature range 730ā820Ā°C and anneal times of several hours or less, V_3Si is formed at a squareāroot rate in time. The activation energy of this process is 2.0Ā±0.2 eV
Silicon implantation in GaAs
The electrical properties of room-temperature Si implants in GaAs have been studied. The implantations were done at 300 keV with doses ranging from 1.7Ć10^13 to 1.7Ć10^15 cm^ā2. The implanted samples were annealed with silicon nitride encapsulants in H2 atmosphere for 30 min at temperatures ranging from 800 to 900Ā°C to electrically activate the implanted ions. Results show that the implanted layers are n type, which implies that the Si ions preferentially go into Ga sites substitutionally. For low-dose implants, high (~90%) electrical activation of the implanted ions is achieved and the depth distribution of the free-electron concentration in the implanted layer roughly follows a Gaussian. However, for high-dose implants, the activation is poor (<15% for a 900 Ā°C anneal) and the electron concentration profile is flat and deeper than the expected range
Ion mixing of markers in SiO2 and Si
The amount of atomic mixing in amorphous SiO2 and Si is studied by measuring the redistribution of thin metal markers due to irradiation with 300-keV Xe+ ions. In SiO2, the mixing efficiency appears to be independent of the chemical nature of marker atoms and can be explained in terms of a linear cascade model. In Si, the mixing is found to correlate with thermally activated diffusivities of the marker species
Chemical effects in ion mixing of a ternary system (metal-SiO_2)
The mixing of Ti, Cr, and Ni thin films with SiO_2 by lowātemperature (ā196ā25āĀ°C) irradiation with 290 keV Xe has been investigated. Comparison of the morphology of the intermixed region and the dose dependences of net metal transport into SiO_2 reveals that long range motion and phase formation probably occur as separate and sequential processes. Kinetic limitations suppress chemical effects in these systems during the initial transport process. Chemical interactions influence the subsequent phase formation
Magnetoelectric properties of magnetite thin films
Resistivity, DC Hall effect and transverse magnetoresistance measurements were made on polycrystalline thin films of magnetite (Fe3O4) from 104K to room temperature. The Verwey transition is observed at TV=123K, about 4K higher than reported for bulk magnetite. The ordinary and extraordinary Hall coefficients are negative over the entire temperature range, consistent with negatively charged carriers. The extraordinary Hall coefficient exhibits a rho 1/3 dependence on the resistivity above TV and a rho 2/3 dependence below TV. The magnetoresistance is negative at all temperatures and for all magnetic field strengths. The planar Hall effect signal was below the sensitivity of the present experiment
Pulsed electron beam induced recrystallization and damage in GaAs
Single-pulse electron-beam irradiations of 300-keV 10^(15)Kr+/cm^2 or 300-keV 3Ć10^(12)Se+/cm^2 implanted layers in unencapsulated GaAs are studied as a function of the electron beam fluence. The electron beam pulse had a mean electron energy of ~-20 keV and a time duration of ~-10^(ā7) s. Analyses by means of MeV He + channeling and TEM show the existence of narrow fluence window (0.4ā0.7 J/cm^2) within which amorphous layers can be sucessfully recrystallized, presumably in the liquid phase regime. Too high a fluence produces extensive deep damage and loss of As
Tantalum-based diffusion barriers in Si/Cu VLSI metallizations
We have studied sputter-deposited Ta, Ta36Si14, and Ta36Si14N50 thin films as diffusion barriers between Cu overlayers and Si substrates. Electrical measurements on Si n + p shallow junction diodes demonstrate that a 180-nm-thick Ta film is not an effective diffusion barrier. For the standard test of 30-min annealing in vacuum applied in the present study, the Ta barrier fails after annealing at 500 Ā°C. An amorphous Ta74Si26 thin film improves the performance by raising the failure temperature of a /Ta74Si26(100 nm)/Cu(500 nm) metallization to 650 Ā°C. Unparalled results are obtained with an amorphous ternary Ta36Si14N50 thin film in the Si/Ta36Si14N50 (120 nm)/Cu(500 nm) and in the Si/TiSi2(30 nm)/Ta36SiN50 (80 nm)/Cu(500 nm) metallization that break down only after annealing at 900 Ā°C. The failure is induced by a premature crystallization of the Ta36Si14N50 alloy (whose crystallization temperature exceeds 1000 Ā°C) when in contact with copper
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