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We compare the performance, stability and microstructure of Si/Gd multilayers containing thin barrier layers of W, [B.sub.4] C, or Si[N.sub.x], and determine that multilayers containing 0.6 nm thick W barrier layers at each interface provide the best compromise between high peak reflectance in the extreme ultraviolet near [lambda] 60 nm and good stability upon heating. The Si/W/Gd films have sharper interfaces and also show vastly superior thermal stability relative to Si/Gd multilayers without barrier layers. We find that these structures have relatively small compressive film stresses, and show good temporal stability thus far. We measured a peak reflectance of 29.7% at [lambda] = 62.5 nm, and a spectral bandpass of [DELTA][lambda] = 9 nm (FWHM), for an optimized Si/W/Gd multilayer having a period d = 32.0 nm. [c] 2009 Optical Society of America OCIS codes: 230.4170, 310.1620, 310.6860, 340.0340, 350.1260.

In this paper, we describe the development of multilayer (ML) thin films suitable for flux concentrators (FC). We prepared ML films having magnetic thicknesses n x [t.sub.F] in the range of 400 [Angstrom]. to 3000 [Angstrom] by ion beam deposition (IBD). The films exhibit Ruderman-Kittel-Kasuya-Yosida (RKKY) long range antiferromagnetic (AF) coupling through very thin Ru interlayers. We prepared two types of samples: (CoFeB [t.sub.F]/Ru [t.sub.Ru])xn and (NiFe [t.sub.F]/Ru [t.sub.Ru])xn, where CoFeB is [([Co.sub.70][Fe.sub.30]).sub.80at%][B.sub.20at%] and NiFe is [Ni.sub.81][Fe.sub.19]. The former has good thermal stability and high magnetic moment while the latter, previously reported, has poor thermal stability and low spontaneous magnetic moment. We discuss the magnetic properties of the films in terms of the remanent magnetic moment Mr and saturation field [H.sub.s]. Despite having higher spontaneous magnetic moment of 1200 emu/[cm.sup.3], (CoFeB/Ru)xn films with adequate magnetic properties for sensor-in-gap devices with FC could not be prepared. By contrast, samples consisting of NiFe350 [Angstrom]/(Ru7 [Angstrom]/NiFe350 [Angstrom])x7 exhibited suitable magnetic properties. We lithographically patterned the films into FC and test structures to investigate their magnetization processes by anisotropic magnetoresistance (MR) measurements. The MR curves indicate magnetization processes by uniform rotation and show absence of hysteresis. Index Terms--Flux concentrator, multilayer, RKKY.

We investigate the effect of the number of bilayers (total film thickness) on the (001) texture development, [L1.sub.0] ordering reaction and magnetic properties in multilayered [[FePt/MgO].sub.6] films that were sputter deposited on thermally oxidized Si substrates. We obtained nearly perfectly [L1.sub.0] (001) oriented nanocomposite films when the initial multilayer structure was [[FePt 2.8 nm/MgO 3.2 nm].sub.6] and the total film thickness was 36 nm. When the film thickness was thicker than about 36 nm or the film was overaged, the grain orientation of the film developed in a random direction. The evolution of the (001) texture was favorable when the total film thickness was thin enough for the strain generated during the ordering transformation to relax in the plane normal direction, thus satisfying the plane stress condition. In addition, the disordered fcc FePt (200) texture grown on (200)-textured MgO in the as-deposited state also affected the [L1.sub.0] (001) texture evolution. Index Terms--FePt, MgO, nanocomposite, thickness, (001) texture.

Magnetic multilayered thin films with perpendicular anisotropy have been patterned into nanoscale islands by ion-milling with an oxygen-plasma patterned carbon hard mask. The islands have been studied by scanning electron microscopy (SEM) and magnetic force microscopy (MFM) to determine the switching field distribution and its origin. Larger islands exhibit coercivities of ~ 450 kA/m (5.6 kOe), but coercivity falls rapidly when island diameter falls below 40 nm. The switching field distribution becomes larger in absolute terms and as a fraction of the coercivity as island diameter falls. The origin of these effects is thought to be edge damage during ion milling and intrinsic defects (grain boundaries or dislocations) in the original magnetic thin film. Index Terms--Bit patterned media, magnetic recording magnetic thin films, nanostructures, switching field distributions, temperature.

Magnetic properties of FeCoSi/native-oxide multilayer films, prepared by DC magnetron sputtering and exposure to oxygen in a sequence, have been investigated. It is found that the appropriate thicknesses of the native-oxide layers and FeCoSi layers are very important in decreasing coercivity [H.sub.c] of the multilayered films, which may be caused by the exchange coupling between the FeCoSi particles through the oxide. A minimum [H.sub.c] value of 8.4 Oe was obtained for the [[FeCoSi (20 [Angstrom])/ native-oxide].sub.50] multilayer film with the largest in-plane uniaxial anisotropy field [H.sub.k] of 130 Oe. The real part [mu]' of complex permeability of this sample is more than 100 and flattens almost to 2.5 GHz, while the imaginary part [mu]' is less than 50 for f < 2.5 GHz. The ferromagnetic resonance frequency is as high as 3.9 GHz, implying that the film is promising for high-frequency applications. Index Terms--High frequency, multilayer films, permeability, soft magnetic.

Results concerning the preparation and magnetic characterization of electrochemically deposited [[Fe.sub.80][Ga.sub.20]/[Co.sub.75][[Fe.sub.10][B.sub.15]].sub.n] multilayered films and nanowire arrays are reported for the first time. The deposition bath consisted in a single mixed solution of FeS[O.sub.4] x 7[H.sub.2]O, [Ga.sub.2][(S[O.sub.4]).sub.3] x [H.sub.2]O, COS[O.sub.4] x 7[H.sub.2]O, [C.sub.2][H.sub.10]BN, and [H.sub.3]B[O.sub.3]. The layers have been deposited successively by changing the electrodeposition potential. The composition and thickness of the different layers were tailored through optimizing deposition parameters such as buffer additives and applied voltage. Two hundred sequences multilayered nanowires were electrodeposited into commercially available nanoporous alumina membranes with pore diameters of 100 nm and lengths of 50 [micro]m. Multilayered films 4-5 [micro]m thick have been obtained by electrodepositing 50 consecutive sequences of FeGa and CoFeB. The multilayered structures consisting FeGa magnetostrictive alloy and CoFeB amorphous magnetic material are magnetically soft ([H.sub.c] does not exceed 1.6 kA/m). Index Terms--Electrodeposition, exchange magnetostriction, magnetostrictive materials, multilayered nanowire arrays.

The influence of the Co layer thickness as well as the number of repetitions N on the magnetic properties of (Co/AU)N multilayers was investigated systematically using magneto-optical techniques, vibrating sample magnetometry, and magnetic force microscopy. The studies focused on the characteristics of magnetic hysteresis loops in connection with magnetic domain structure parameters. Increasing the repetitions number, an out-of-plane magnetization ordering is created for Co layers with a thickness larger than the single-layer thickness at which the spin reorientation transition occurs. Index Terms--Cobalt, magnetic domains, magnetization reversal, multilayer films.

We investigated the out-of-plane anisotropy of [Co.sub.50][Fe.sub.50]/Tb multilayer film with changing the thickness of Tb layer and applying an inplane filed of 200 Oe during film deposition. A strong out-of-plane anisotropy was found only for the multilayer with small thickness of Tb layer ([t.sub.Tb] = 1 nm) and was suppressed significantly by the application of an inplane magnetic field of 200 Oe during deposition, resulting in an inplane anisotropy. It was also found that the application of the magnetic field caused the enhanced intermixing between CoFe and Tb layers to form Co-Tb and Fe-Tb alloys at the interface of the layers. While the origin of the out-of-plane anisotropy and the change of the out-of-plane to inplane anisotropy with the application of inplane field of 200 Oe are not understood completely, it seems that there is a strong correlation between the out-of-plane anisotropy and the formation of the alloys and the stress at the interface. Index Terms--CoFe/Tb multilayer, intermixed alloys, magnetic field, out-of-plane anisotropy.

A systematic study of in-plane and out-of-plane exchange biases in FePt/FeMn multilayers epitaxially deposited onto MgO(100), MgO(110), MgO(111) substrates by ion beam sputter-deposition system was performed. It is found that the surface and volume anisotropy constants are largest when samples are growth in (100) direction. While the FePt thickness dependence of the blocking temperature show a similar behavior for samples grown with different crystalline orientations, the dependences of exchange bias field and the unidirectional anisotropy constant on FePt thickness behave differently for different orientations. The ratio of in-plane and out-of-plane exchange biases is not only strongly dependent on crystalline orientation but also on thickness of FePt layers suggesting that the spin structure at the interface in multilayer thin films may not be the same as that of the antiferromagnetic bulk. Index Terms--Blocking temperatures, multilayer thin films, out-of-plane exchange bias, surface anisotropy.

Analytical expressions for current to a cylindrical Langmuir probe at rest in unmagnetized plasma are compared with results from both steady-state Vlasov and particle-in-cell Simulations. Probe bias potentials that are much greater than plasma temperature (assumed equal for ions and electrons), as of interest for bare conductive tethers, are considered. At a very high bias, both the electric potential and the attracted-species density exhibit complex radial profiles; in particular, the density exhibits a minimum well within the plasma sheath and a maximum closer to the probe. Excellent agreement is found between analytical and numerical results for values of the probe radius R close to the maximum radius [R.sub.max] for orbital-motion-limited (OML) collection at a particular bias in the following number of profile features: the values and positions of density minimum and maximum, position of sheath boundary, and value of a radius characterizing the no-space-charge behavior of a potential near the high-bias probe. Good agreement between the theory and simulations is also found for parametric laws jointly covering the following three characteristic R ranges: sheath radius versus probe radius and bias for R << [R.sub.max]; density minimum versus probe bias for R [congruent to] [R.sub.max]; and (weakly bias-dependent) current drop below the OML value versus the probe radius for R > [R.sub.max]. Index Terms--Asymptotic theory, bare electrodynamic tether, high-voltage sheath, Langmuir probe current, particle-in-cell (PIC) simulations, steady-state Vlasov simulations.

Here, it is demonstrated that similar chemical species within a multicomponent sample can be distinguished, down to the single-molecule level, by means of their surface-enhanced vibrational fingerprints. Surface-enhanced resonance Raman scattering spectra and 2D spatial intensity maps are recorded from thin Ag nanoparticle films coated with fatty acid Langmuir-Blodgett monolayers containing one-to-one binary mixtures, at varying concentrations, of two dye molecules of similar absorption and scattering cross section (n-pentyl-5-salicylimidoperylene and octadecylrhodamine B). The results reveal the change in the distribution of the two dyes within the monolayer, and the breakdown of ensemble spectral averaging, which occur as the single-molecule regime is approached. It is found that the unimolecular level is reached when 1-10 molecules of each dye occupy the 1-[micro][m.sup.2] scattering areas probed by the laser. These signals are attributed to the rare spatial coincidence of isolated target analyte molecules and localized electromagnetic hot spots in the nanostructured metal film. The bianalyte nature of the samples provides strong corroborative support for the attribution of spectra to single molecules at high dilution, while the effect of domain formation/aggregation is found to be important at higher concentrations.

Colloidal particles prepared by using the layer-by-layer technique are increasingly finding application in diagnostics, drug delivery, and sensing. Herein, we outline methods for applying three established techniques, confocal laser scanning microscopy (CLSM), flow cytometry, and differential interference contrast (DIC) microscopy, to characterize ultrathin films of poly(styrenesulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) assembled on silica particles. Both CLSM and flow cytometry require the use of fluorescently labeled polyelectrolytes (PEs). The film homogeneity can be assessed using CLSM, while flow cytometry allows analysis at unparalleled speed (thousands of particles per second) with unprecedented sensitivity (

Skeletonema costatum was grown in an outdoor mesocosm to test the hypothesis that fluctuations in irradiance brought about by changes in mixing time and depth can reduce diatom growth and biomass in the turbulent mixed layer. The light environment and mixing regime within the mesocosm were comparable to those in shallow lakes and coastal waters. Experiments showed no significant differences for 24-h mean and 7-day mean chlorophyll a and carbon-specific growth for mixed depths of 1 m and 3 m, and mixing times between 4 min and 65 min. Fluctuations in irradiance brought about by turbulent mixing had no significant effect on specific growth. The relationship between mixed depths and critical depths for S. costatum was therefore independent of fluctuations in irradiance in the turbulent mixed layer. The results indicated that to control growth of S. costatum mixed depths would have to exceed photic depths by a factor of 15, instead of the conventionally accepted factor of 5. Thus, it is likely that artificial mixing of shallow (< 10 m) eutrophic waters will be more effective in controlling 'slow-growing' summer biomass than 'fast-growing' spring blooms dominated by diatoms., Introduction Although the relationship between light and phytoplankton growth in laboratory cultures is well researched, the effect of variability in light experienced by plankton cells in the mixed layer is [...]

Silicalite-1 films supported on both sides of glass plates are prepared and hemicyanine dyes with different alkyl chain lengths are induced into the silicalite-1 films by dipping SL/Gs into each methanol solution of HC-n for 1d. The included numbers of HC-n per channel (Nc) generally decreased with increasing n.

Two soluble phthalocyanine derivatives, 2, 9, 16-tri(tert-butyl)-23-(10-hydroxydecyloxy) phthalocyanine (1) and 2, 9, 16-tri(tert-butyl)-23-(10-hydroxydecyloxy) copper phthalocyanine (2) were used as semiconductor layers in organic thin-film transistors (OTFTs) based on their Langmuir - Blodgett (LB) films. The highest occupied molecular orbital and the lowest unoccupied molecular orbital were determined, and the energy band diagram of their OTFT can be deduced by the cyclic voltammetric measurements.

Byline: Adel F. Antippa (1) Keywords: Langmuir; monolayer; domain; lattice; structure Abstract: We make a mathematical analysis of the structure of the two dimensional lattice formed by the centers of parallely aligned and arbitrarily oriented spherocylindrical phospholipidic molecules hexagonally packed in cylindrical domains forming a monomolecular Langmuir film at the liquid--gas interface. The analysis is carried out as a function of the tilting angle I, and the tilting azimuth I. We give a number of expressions for the lattice radius vector, and introduce the Lattice Generating Operator. We also present a number of theorems dealing with the existence and characteristics of the common points of tangency, the double stationary points, the locus circles, and the envelop circles, related to the lattice sites. Author Affiliation: (1) Departement de Physique, Universite du Quebec a Trois-Rivieres, 3351 Boul. des Forges, Trois-Rivieres, Quebec, Canada, G9A 5H7 Article History: Registration Date: 08/10/2004

The mechanism of the meniscus oscillations and the stripes formation within the deposited fatty acid monolayer is theoretically analyzed on the basis of a supposition of concentration polarization within the solution during the deposition process. The results reveal that the proposed mechanism corresponds to the observed meniscus behavior during oscillations and agrees with numerous experimental data on adhesion work, contact angles, and maximum monolayer deposition rate.

The observation of overtones and combinations in the SERRS spectra of single molecules dispersed in Langmuir--Blodgett monolayers is confirmed for a family of molecules. The detection of fundamentals, combinations, and overtones in single-molecule spectra of a series of perylenetetracarboxylic diimides (PTCD) is achieved with spatially resolved surface-enhanced resonance Raman scattering (SERRS). The Langmuir--Blodgett technique is used to create monomolecular thick films on metal islands containing on average one probed molecule within the field of view of the Raman microscope. The enhancement needed for single-molecule detection is achieved through the multiplicative effects of electromagnetic enhancement by metal nanostructures and resonance Raman enhancement by excitation into molecular electronic absorption bands. Overtone and combination progressions are well resolved in the average SERRS spectra of all three PTCD molecules.

The electrochemical behavior of multilayer films formed by iron porphyrins deposited on an edge plane graphite electrode has been examined under anaerobic conditions. In the scan rate interval (1-250 mV/s) where the electrode reaction is reversible, CV diagrams of these films demonstrate substantial deviations from ideality in broadening and separation of the peaks. A model that describes the observed behavior is proposed by taking into account the potential distribution at the electrode/film interface and the concentration dependence of surface activity coefficients. The peak separation is described in terms of the electric double layer that affects the potential difference driving the electrode reaction. The effective potential difference deviates from the applied value due to the potential distribution across the film. The interfacial potential distribution depends on the ionic concentration inside the film. When different ionic concentrations are assumed for oxidation and reduction, different shifts from the applied potential lead to a hysteresis of the peaks. The peak broadening is modeled by using the lattice theory expression for the surface activity coefficients. The model shows that the midpoint potentials of the redox centers depend on the ionic concentration inside the film. At low ionic concentrations, they are remarkably close to the midpoints of the cytochrome c oxidase heme [a.sub.3]/[Cu.sub.B] site.

Recent achievements in magnetic transmission soft X-ray microscopy are reviewed. The magnetic contrast is given by X-ray magnetic circular dichroism, i.e., the dependence of the absorption coefficient of circularly polarized X-rays on the projection of the magnetization in a ferromagnetic system onto the photon propagation direction. A lateral resolution down at 25 nm is provided by Fresnel zone plates used as optical elements. Recording the images in varying external magnetic fields, inherent chemical specificity, a high sensitivity to thin magnetic layers due to the large contrast, and the possibility to distinguish between in-plane and out-of plane contributions allows detailed studies of magnetization reversal processes in magnetic patterned elements and thin films. Micromagnetic simulations support the experimental findings. The potential to study spin dynamics will be briefly outlined. Index Terms--Magnetic domains, magnetic multilayered films, magnetization reversal, X-ray imaging.

Thermal stability of coupled granular/continuous (CGC) perpendicular media is supported by fundamental modeling and experimental results, including spin-stand testing. By incorporating the interlayer exchange coupling into the model, the simulation result suggests that the CGC structure is capable of achieving the energy barrier of [K.sub.u]V/[k.sub.B]T required for 1 Tbit/[in.sup.2] recording density. To demonstrate the CGC approach, we investigate a new class of CGC perpendicular media consisting of a Pt-rich CoPtCr layer with poor Co-Cr phase segregation and a thin Pt layer. The addition of these layers improves the nucleation field of the Co[Cr.sub.18][Pt.sub.12] medium from +420 to -600 Oe and the thermal decay of the output is reduced from 2.23% to 0.10% per decade. Unity squareness was obtained by using a thin Pt capping layer and resulted in a small decay rate of 0.21% per decade. The new CGC media showed no degradation of SNR compared to the base granular medium. Similar to CGC media utilizing a multilayer capping structure, the CGC medium with a Pr. rich CoPtCr or Pt capping structure improved the thermal stability without compromising SNR. The simplicity of these new CGC structures also greatly simplifies the deposition process. Index Terms--Continuous layer, granular layer, perpendicular media, Pt layer, signal-to-noise ratio, thermal stability.

Results reveal that some polymers display pi-aggregates resembling edge-on-structure at the air-water interface, while monolayer Langmuir-Blodgett films of the polymers show a reduction in the quantum yields. Polymers that do not form pi-aggregates exhibit a highly emissive face-on-structure at the air-water interface.

We present our results of coating a first set of optical elements for an extreme-ultraviolet (EUV) lithography system. The optics were coated with Mo-Si multilayer mirrors by dc magnetron sputtering and characterized by synchrotron radiation. Near-normal incidence reflectances above 65% were achieved at 13.35 nm. The run-to-run reproducibility of the reflectance peak wavelength was maintained to within 0.4%, and the thickness uniformity (or gradient) was controlled to within [+ or -] 0.05% peak to valley, exceeding the prescribed specification. The deposition technique used for this study is an enabling technology for EUV lithography, making it possible to fabricate multilayer-coated optics to accuracies commensurate with atomic dimensions. OCIS codes: 310.1860, 110.3960, 340.7470, 260.7200, 220.3740.

Molecular 'nanowire' structures composed of the charge transfer complex of a bis-tetrathiafulvalene substituted macrocycle and tetrafluorotetracyanoquinodimethane were constructed on mica substrates by employing the Langmuir-Blodgett technique. The nanowires transferred from a dilute aqueous potassium chloride subphase had typical dimensions of 2.5 nm x 50 nm x 1 [micro]m. The nanowires are oriented to specific directions, corresponding to the directions of the potassium-ion array on the mica surface having sixfold symmetry. Such correlation between the nanowires and the substrate surface was also observed when a dilute aqueous rubidium chloride subphase was used. On the other hand, the correlation completely disappeared when the subphase contained divalent cations, indicating that the molecular nanowires orient by recognizing the monocation array on the mica surface. The nanowires formed by the vertical dipping method coexist with the monolayers. Only nanowire structures are, however, observed when we apply the horizontal lifting method. Based on the crystal structure of a related complex, a possible structure of the nanowires is presented. The conductivity of the nanowires was estimated to be of the order of [10.sup.-3] [S*cm.sup.-1]. The nanowires formed specific (regular) structures such as T-shape junctions, suggesting their use in construction of future molecular nanoscale devices.

Byline: A.F. Antippa (1), J.-J. Max (2), C. Chapados (2) Keywords: molecular; organization; Langmuir; films; gas; liquid; interface; boundary effects; hexagonal; packing; orientation; spherocylindrical; rod-like; molecules Abstract: We study the organization of spherocylindrical molecules inside a freely rotating right circular cylindrical domain at the gas/liquid interface. The analysis is made under the assumption that the molecules are rigid and close packed, and that they are oriented parallel to each other. The direction and angle of their common orientation are completely arbitrary. We obtain exact analytic expressions for the lattice of molecular centers and its boundaries as a function of molecular dimensions, molecular orientation, and domain size. As a first application, we derive the number of molecules in a domain, and the packing fraction. The results obtained are essential when attempting to analytically model a Langmuir film where the global order of the film is less than the local order of the domains. Author Affiliation: (1) Departement de Physique, Universite du Quebec a Trois-Rivieres Trois-Rivieres, Quebec, Canada, G9A 5H7 (2) Departement de Chimie-Biologie, Universite du Quebec a Trois-Rivieres Trois-Rivieres, Quebec, Canada, G9A 5H7 Article History: Registration Date: 08/10/2004

Research demonstrates the synthesis of an amphiphilic platinum complex with pyridine compound and its surface-active properties. Data indicate that in the absence of fatty acids, the complex forms a stable Langmuir-Blodget (LB) multilayer film, which exhibits strong emission characteristics and suppressed platinum-platinum interactions.

The amphiphilic chelating agent, n-octadecylacetoacetate (C18AA), plays an important role in improving the stability of metal alkoxide-derived gel films on water surface and the quantitativeness of Langmuir-Blodgett (LB) deposition of gel films onto substrates in the 2D sol-gel process. It has the ability to self-form an air/water monolayer and to complex with the metal center of a metal alkoxide.

An experimental study on the hardness behavior of polycrystalline Ti/TiN multilayers with periods in the nanometer scale was found to be similar to the nitride/ nitride and metal/ metal systems. The hardness increases as the decreasing period thickness go beyond the rule-of-mixture for samples with period thickness of (?) 5 nm.

A study measured the electrical characteristics of two similar, multilayered thin films composed of an yttrium barium copper oxide layer, a La4ba4Cu5O13 capping layer and an ultra-thin gold contact layer. Current-voltage characteristics of these samples measured in the flux creep regime showed that they present a low depinning current/critical current ratio and high maximum vortex velocity values within a large temperature range. Experimental methods and findings are presented.

A study investigated the (2234)1(2212)1 and (2245)1(2201)1 superlattice films of bismuth-based oxide superconductors by X-ray diffraction especially in-plane. It reports the impact of the change in in-plane lattice constants by the superlattice formation which would lead to the transfer of the holes from the over-doped unit to the under-doped unit. It is suggested that stress might induce the charge transfer from the over-doped layers to the under-doped layers such that the stress in both over-doped and under-doped unit might be released.

The through-film electrical conductivity of multilayered thin films of hexadecylquinolinium tricyanoquinodimethanide was investigated as a function of temperature. The current was observed to be usually smaller at low temperature. Electrical rectification was detected between 370 and 105 K, with a rectification ratio as large at 105 K as it is at room temperature. Electrical rectification was surmised to be caused by an intramolecular electron transfer.

We fabricated submicrometer-thick optical polarizing films at a wavelength of 1300 nm with extinction ratios of [greater than or equal to]30 dB by stretching periodic multilayers of silver island layers and glass layers. We compared the measured and theoretical optical characteristics of the polarizing films. The measured optical characteristics were quantitatively different from preliminary theoretical ones reported in an earlier paper [Opt. Lett. 16, 964 (1991)]. We have improved the theory by considering the distribution in silver island shapes and the difference between the stretching ratios of the glass layers and the silver islands. We have successfully elucidated the optical characteristics of the fabricated optical polarizing films.

The creation and properties of La/Fe multilayers with a helical magnetic structure imprinted from growth conditions of, rather than magnetic interactions between layers, are discussed. During deposition, samples were rotated in an external field of 3 Oe to form a helical structure. It is shown that the imprinted helical magnetic structures that are stable in time can only be permanently erased by magnetic fields over 90 Oe.

Monolayer and multilayer modified semiconductor ITO electrodes with amphiphilic C(sub 60)-EDTA derivatives and photo-driven electron transfer at the electrode-electrolyte interface are investigated. Amphiphilic C(sub 60)-EDTA derivatives can form stable monolayer at the air-water interface and the monolayer can be deposited onto an ITO substrate. Multiple deposition to form a stack of monolayers is facile when the number of layer is below 7. The direction of electron flow in the C(sub 60)EA-ITO-electrolyte system can be modulated by the pH in the solution.

The multilayer formation of a series of chiral liquid crystal molecules at the air/water interface has been studied by measuring their pi-A and surface potential-area isotherms. It has been discovered that some smectic liquid crystal molecules deposited on solid substrates by thermal evaporation in vacuum can have layered structures. The self-assembly of L2, L4, L6 and L8 on water is linked with their hydroxyl and with the number of CH2 groups in the terminal group.

The circular dichroism (CD) and ultraviolet-visible absorption spectra of Langmuir-Blodgett (LB) films made from nonracemic helicene have been analyzed. The CD and absorption spectra of the LB films are similar to those of solutions of aggregates and not of monomers. This shows that molecules form long columns in the LB films and in dodecane solutions. There is also a similarity in the interlayer spacings of the LB films to the diameter of the molecular columns that comprise bulk nonracemic helicene.

The giant magnetoresistance properties of vapor deposited metal multilayers are commonly influenced by the structure and defects in the films. A three-dimensional molecular dynamics approach was therefore created to examine the role of vapor atom impact energy on film structure as well as to simulate the growth of Ni/Cu/Ni multilayers. This can be easily implemented suing ion beam deposition.

The giant magnetoresistance (GMR) effect in systems of spherical or cylindrical ferromagnetic granular films is studied using an extended effective-medium approach model. Results showed the volume-fraction dependence of GMR for varying spin asymmetric factors. It was found that the larger the spin-asymmetric factor, the more significant the GMR effect. GMR curves were also found to be dependent on the granular radius.

High levels of interconnection line stress are a serious reliability problem for the integrated circuit industry. These stresses, which are due to the thermal expansion coefficient difference between the line and its surroundings, as well as to nonequilibrium film growth, can lead to failure mechanisms such as voiding and cracking. Historically, stresses in these lines have typically been modeled using a fixed configuration at the final process step. The stresses are calculated as the model is cooled to room temperature. We have developed models to calculate stresses in interconnection structures as a function of process step, such as film deposition, etching, and thermal cycles. During processing both thermal and intrinsic stresses are induced, and continuously changed by subsequent process steps. This paper presents such an analysis of simple interconnection structures which contain two-level aluminum (AI) metal layers and a tungsten (W) via connection. Stress histories of the metal and via layers are obtained and discussed. This paper also discusses the effects on interconnection stress when intrinsic stresses in various layers are taken into account. Index Terms - FEM analysis, interconnection line, intrinsic stress, stress history, thin film.

The growth of aluminum(III) alkanebisphosphonate multilayer thin films on gold surfaces in aqueous solutions was investigated by probing the surface charge following alternate treatments with anionic phosphonate and cationic Al(III). This was accomplished by determining the force between a modified silica tip of an atomic force microscope (AFM) and the film-covered gold substrate. The AFM force measurements revealed that the formation of the films followed a regular layer-by-layer growth mechanism as evidenced by the occurrence of surface charge reversal with each adsorption step. However, the quantitative surface charge data, obtained by theoretical fits of the force data to solutions of the complete nonlinear Poisson-Boltzmann equation with a knowledge of the silica probe surface potential, indicated that the films became less ordered with an increase in the number of layers. The AFM force measuring technique was also employed to monitor the immobilization of both single-stranded (ss) and double-stranded (ds) DNA on positively charged surfaces (i.e., aluminum(III)- and ammonium-terminated surfaces) and their subsequent interactions with a transition metal chelate, Ru[[(phen).sub.3].sup.2+]. The force measurement results showed that both the ss-DNA and ds-DNA could be immobilized on positively charged surfaces, while only the ds-DNA showed interaction with Ru[[(phen).sub.3].sup.2+].

The photoconductive properties of a surface active anthracene derivative incorporated in an anisotropic Langmuir-Blodgett (LB) film are analyzed to determine the extent the photoconductivity can be extrapolated to LB-films of 2A7. To achieve this, information was gathered regarding the charge generation and recombination mechanism of nonsensitized in-plane photocurrents on variation of several experimental parameters. Further, the generation of photosensitized hole currents in the 2A7 multilayer was examined by placing amphiphilic rhodamine derivative and arachidic acid on top of the 2A7 multilayers. The results are discussed.

Frictional characteristics of several types of boundary lubricants were tested using scanning probe microscopy (SPM). These include Langmuir monolayers of stearic acids (STA), their cadmium salts (STCd), self-assembling monolayers (SAMs) of alkylchlorsilanes, and complexes of STA with rigid naphthoylene benzimidazole (x-NBI) fragments. We observed that a Langmuir monolayer deposited on a silicon surface had a very low friction coefficient against a silicon nitride tip (about 0.01-0.05) but also low mechanical stability. SAMs were found to be much more stable but had the drawback of growth in the friction coefficient at high sliding velocities. Composite NBI/STA monolayers were much more stable and were not damaged by the highest normal load applied. The frictional behavior of different monolayers was analyzed in relation to their structural organization (the type of tethering to the surface and packing density). We introduced a figure of merit (FOM) parameter which allowed comparison of frictional properties of very different lubricant materials to those of the supporting substrate. For Langmuir monolayers the FOM increased strongly with surface packing density whereas for SAMs and x-NBI/STA complexes it possessed a maximum at surface densities in the range 3.5-4.5 molecules per [nm.sup.2]. Because of the possibility of tailoring the surface packing density of aliphatic tails in the complexes, they are a promising alternative to both LB films and SAMs. For such composite monolayers, the surface packing density can be optimized to give a desired frictional behavior.

A new concept of epitaxial silicon (Si) wafers (NC epi.) in which [p.sup.-]([n.sup.-]) thin-film layers are grown on [p.sup.-]([n.sup.-]) Czochralski (CZ)-Si substrates (substrate resistivity: approximately 10 [ohms] cm) is proposed for metal oxide semiconductor (MOS) ultra large-scale integrated circuits (ULSI's) as a starting material. A thickness of 0.3-1 [[micro]meter] for the epitaxial layer ([p.sup.-]/[p.sup.-] structure) is shown to be sufficient for improving the gate oxide integrity for MOS-ULSI's. The epitaxial layer grown on Si substrate greatly reduces weak spots in the gate oxide layer by covering microdefects in the CZ-Si represented by crystal originated particle (COP). The [p.sup.-]/[p.sup.-] thin-film epitaxial structure results in very controlled resistivity for the electrically active region in the device, which in turn results in a lower growth cost and higher feasibility for use in current ULSI's. The features of NC epi. in combination with proximity gettering is presented. An application of NC epi. in shallow-trench isolation processes discussed considering retrograde-type well-tub. The amenability of epitaxial wafers to wafer enlargement (over 300 mm) is discussed to eliminate bad effects of COP.

An experimental investigation of W/C, W/Ti, Ni/Ti, and Ni/V multilayers is presented that uses synchrotron radiation in the soft-x-ray energy region between 100 and 1500 eV with special emphasis on the water window. The multilayers were designed as normal incidence reflectors and for polarimetry purposes around the Brewster angle. Both reflection and transmission multilayers were prepared for use as linear polarizers and phase retarders, respectively, to produce or analyze circularly polarized light. Their period was optimized to achieve maximum reflectance at the 1s absorption edge of C (284 eV) and the 2p edges of Ti (454 eV) and V (512 eV), respectively. At these edges the multilayers show an enhancement of reflectance and energy resolution that is in accordance with theoretical calculations.

The modified Sanderson formalism for computation of partial charge on atoms was found to produce extremely good correlation between the atomic partial charge in organic molecules and core level binding energies determined through X-ray photoelectron spectroscopy. The MS technique was employed to determine partial charges on the carbons in Langmuir Blodgett films of lead arachidate and chloroplatinic acid-octadecylamine complexes and from the atomic charges, expected C 1s chemical shifts.

The phase shift upon transmission of a nonabsorbing multilayer is shown to be a monotonically decreasing function of the wave number, with an average slope proportional to the optical thickness of the coating. Two limiting situations of the phase shift upon reflection are examined: In one the phase monotonically increases with wavelength, and in the other the phase oscillates. The phase shift upon reflection is derivable from Kramers-Kronig-type relationships, provided the radiant reflectance and the Blaschke factors are known. Characteristic features of the refractive-index profile related to these factors are discussed. Key words: Thin films, multilayer, phase, reflectivity.