For [Co(3 angstrom)/Pt(10 angstrom)]_n multilayers and FePt(111) L1₀ ordered films exposed to energetic ion beam irradiation, we have experimentally determined the dependence of the perpendicular coercivity on ion dose, for a variety of ion species and energies. A simple model based on ballistic displacement of Co (or Fe) atoms from ordered configurations is presented, which predicts an exponential decline of anisotropy with ion dose. The perpendicular coercivity for these samples is indeed found to decline in this way. The ballistic displacement model, evaluated using SRIM Monte Carlo simulation, roughly reflects the observed dependence on ion species and energy. However, the experimental data would demand a displacement probability per incident ion many times larger than that obtained from SRIM.

A magnetically-driven method for controlling nano- dimensional porosity in sol gel derived metal oxide films, including TiO₂, Al₂O₃, and SnO₂, coated onto ferromagnetic amorphous substrates, such as the magnetically-soft Metglas alloys, is described. Based on the porous structures observed dependence on external magnetic field, a model is suggested to explain the phenomena. Under well-defined conditions it appears that the sol particles coming out of solution, and undergoing Brownian motion, follow the magnetic field lines oriented perpendicularly to the substrate surface associated with the magnetic domain walls of the substrate; hence the porosity developed during solvent evaporation correlates with the magnetic domain size.

The surfaces of single-crystal wafers of sapphire and silicon carbide with microelectronic-grade high polish were exposed to a gas-cluster ion beam (GCIB) and significant reductions in roughness were observed. Atomic-force microscopy revealed that the typical initial surfaces consisted of a fine but small random roughness together with relatively large and sharp asperities. The latter were removed efficiently and GCIB smoothing process improvements are reported. The SiC wafers also have a high density of shallow scratch marks and these too were removed, with the average roughness R_a falling below 4 angstrom after the best process. Analysis of the SiC by Rutherford backscattering spectroscopy in channeling mode revealed that when the GCIB process was adjusted so that asperities and scratch marks were removed, there was no increase in near- and at-surface damage. In particular, no lattice damage was observed of the sort typically caused by ion implantation prior to annealing. Significantly, it was found that oxygen gas cluster ion beams provided superior results with SiC as compared with argon GCIB. Surface smoothing mechanisms are proposed to explain these results.

We have studied yield and time evolution of pulsed laser induced photo-luminescence (PL) in proton irradiated and thermally annealed amorphous hydrogenated silicon carbon alloys prepared by Plasma Enhanced Chemical Vapor Deposition (PECVD). The fluorescence spectra are taken at room temperature, using 532 nm, 40 ps laser pulses from a cw pulsed YLF laser source. Three major fluorescence channels have been observed. The corresponding decay times are found to be largely independent from proton irradiation and thermal annealing. Proton irradiation lowers the luminescence yield until it becomes practically quenched for fluences higher than approximately 10¹⁶ cm^-2. The luminescence yield of irradiated samples, however, recovers after thermal annealing and the observed average decay time of the PL intensity signal becomes faster by at least a factor of three compared to the one of the as- deposited sample. Lack of correlation between yield and average time decay suggests a very simple phenomenological model which allows evaluation of the non radiative time constant. The latter is linearly correlated with the photoluminescence yield. Our model suggests that radiative recombination occurs via exciton decay while the non radiative recombination is driven by trapping of carriers in defects states.

The transition to semiconductor design nodes below 100 nm will create high demands on metrology solutions for the detection and chemical characterization of defects and particles throughout all processing steps. The compositional analysis of particles with sizes below about 20 nm is one particular challenge. We describe progress in the development of a highly charged ion based secondary ion mass spectrometry (HCI-SIMS) schemes aimed at addressing this challenge. Using ions like Xe⁴⁸⁺ as projectiles increases secondary ion yields by several orders of magnitude and enables the application of coincidence counting techniques for the characterization of nano-environments of selected species. Additionally, an ion emission microscope was developed for defect imaging and we report examples of its application. We discuss steps of combining beam focusing, coincidence analysis and emission microscopy to enable compositional analysis of sub 20-nm size particles.

In an effort to develop an improved medium for optical communication, chalcogenide glasses are being investigated for waveguide and integrated optical components. These glasses are attractive for integrated optics applications due to their good infrared transmission and high nonlinear Kerr effects. The fact that these glasses can be fabricated in thin films and optical fiber forms constitute a major advantage for future high-speed optical devices applications. However, to advance these novel characteristics, it is crucial to identify the structure/property relationship in the glass, in both bulk and film materials. Rutherford Backscattering Spectroscopy (RBS) is an analytical tool that gives very useful information regarding compositional and structural analysis of the films, as well as a precise measurement of the film's layer thickness. Results obtained showed no apparent variation in composition and small (less than 10%) density variation in single layer As₂S₃ films. Multilayer films, which thickness were measured using SEM images, displayed compositional and density modifications associated with the annealing process. The same calculations were conducted after almost a year from the previous measurements to study changes induced due to film aging. Stoichiometric and thickness modifications, caused by aging, were observed in unannealed structures. No apparent changes were detected in annealed films. Waveguide Raman Spectroscopy was used as a complementary tool to identify the molecular features responsible for the changes.

The present paper investigates the application of the phenomenon of instability development on the charged surface of a photothermoplastic carrier for visualization of interferograms of a hydroelectropump body oscillation during vibration loading. It is demonstrated that the concentration of the surface-active substances determines the value of the resolution capacity due to the reduction of the coefficient of surface tension of the phase rheological media. The characteristics of some PTPC show that the application of photothermoplastic carrier - surface-active substances (PTPC plus SAS) in holography (interferograms) is not only possible, but also necessary. It is determined by the fact that at a quite high holographic sensitivity (up to 10^-7 J/cm²) the frequencies above 1500 mm^-1 can be recorded with the values of diffraction efficiency much more than those for hologen-silver materials. An optical configuration based on the photothermoplastic recording (PTPR) is suggested for the inline optical diagnostics and standardization of the products in the real-time scale. Dry development of the images in the real-time scale and instant fixation of images on the photothermoplastic carriers (PTPC) followed by the computer analysis used to compare the product and the standard allow us to gain in time and areas.

Ion Beam Enhancement and Detection of Latent Fingerprints Using Auger and SIMS Analysis have potential significant forensic applications. The ion implantation process is used to ion beam mix the materials of the latent fingerprints into a substrate, such that the atoms that form the latent fingerprints become an integrated part of the substrate material. The permanent record of the fingerprint can be imaged optically or with a scanning electron microscope. In addition, surface analysis techniques such as Secondary Ion Mass Spectrometry (SIMS), Particle Induced X-ray Emission (PIXE) or Auger Spectroscopy (AES) can be used to identify the chemical composition of the fingerprint material. This work involved ion beam mixing fingerprints into selected classes of substrates and used Auger spectrometry and computer aided Auger mapping to image fingerprints with low concentrations of the fingerprint materials. This combination of techniques produced images of fingerprints with heretofore-unapplied surface analysis techniques. The application of these surface analysis techniques was possible by the ion beam mixing process. Future applications are now possible with utilizing techniques more sensitive to lower concentrations of the fingerprint material. Using modern surface spectroscopy methods it can be possible to detect and map fingerprints at concentrations in parts per billion (ppb).

Experiments with nitrogen torch at atmospheric pressure have been performed in order to identify the role of surface processes in the mechanism of nitrogen transport during nitriding of stainless steel AISI 304. The unusually thick (approximately 175 micrometers ) layers of supersaturated N solid-solution f.c.c. phase have been obtained for 10 min 450 degrees C. Radically different structure have samples treated for 550 degrees C. The scanning electron microscopy (SEM) surface and cross-sectional micrographs reveal that surface topography is indicator of the degree of modification occurring in the nitrided layer. Surface vacancies generated by surface instabilities move deeply into the bulk at elevated temperatures and form highly defected layer with pores and microcracks. The transport of nitrogen in austenitic stainless steel is driven by the fluxes of matrix atoms directed to stabilize surface instabilities. Nitrogen depth profiles simulated on the basis of the model with surface atom relocation process and activation energy 1.1-1.5 eV and including balanced fluxes of atoms in the bulk for relaxation of surface energy are in quantitative agreement with experimental results.

In this paper we show that low energy ion implantation of InP based heterostructures for quantum well intermixing is a promising technique for photonic integrated devices. In order to fabricate complex optoelectronic devices with a spatial control of the bandgap profile of the heterostructure, there is a list of requirements that have to be fulfilled. We have fabricated high quality discrete blueshifted laser diodes to verify the capability of low energy ion implantation induced intermixing for integration. We also adapted this intermixing process to specific heterostructures in order to obtain submicrometer bandgap tuning spatial control.

Preliminary results on the hydrogenation characteristics of vanadium-implanted magnesium films are presented. Magnesium films were prepared by vacuum evaporation. Some of them were then implanted with vanadium in order to improve their kinetics and lower the temperature of operation. The structural and hydrogen sorption properties of pure magnesium as well as ion-implanted magnesium films are described. The effects of vanadium ion implantation on hydrogen diffusion will be discussed.

A new route for nanotube-based applications in molecular electronics was developed. Individual polymer strands were assembled onto single-walled carbon nanotubes (SWNT) and multi-walled carbon nanotubes (MWNT) by mechanical agitation. The SWNT hybrid systems have been characterized by electron microscopy (TEM, STM), optical absorption and Raman spectroscopy and a fully nondestructive technique, using electron paramagnetic resonance (EPR), has been developed to estimate the purity of MWNT soot and hybrids. It is demonstrated that solutions of the polymer are capable of suspending nanotubes indefinitely while the majority of the accompanying amorphous graphite precipitates out of solution. Electron microscopy and Raman scattering indicate that through an intercalation process, the ropes of SWNT are destroyed, resulting in individual nanotubes being well dispersed within the polymer matrix. Moreover, Raman and absorption studies suggest that the polymer interacts preferentially with nanotubes of specific diameters or a range of diameters. STM studies showed that the chiral angle of the underlying nanotube is reflected in the polymer coating, demonstrating that the lattice structure of the SWNT templates the ordering in the coating. This could lead to design of specific polymer architectures for selection of desired chiral angles, and hence specific electronic properties.

We used a kinematical electron scattering model to develop a RHEED based method for performing quantitative analysis of mosaic polycrystalline thin film in-plane and out-of-plain grain orientation distributions. RHEED based biaxial texture measurements are compared to x-ray and transmission electron microscopy measurements to establish the validity of the RHEED analysis method. MgO was grown on amorphous Si₃N₄ by ion beam-assisted deposition (IBAD) using 750 eV Ar⁺ ions and MgO e-beam evaporation. The ion/MgO flux ratio was varied between 0.66 and 0.42. In situ RHEED analysis reveals that during nucleation the out-of-plane orientation distribution is very broad (almost random), but narrows very quickly once well-oriented grains reach a critical size. Under optimal conditions a competition between selective sputtering and surface roughening yields a minimum out-of-plane texture at about 100 angstrom, which degrades with increasing film thickness. The narrowest in- plane orientation distribution (5.4 degrees FWHM) was found to be at an ion/MgO flux ratio between 0.55 and 0.51, in good agreement with previous experiments. The systematic offsets between RHEED analysis and x-ray measurements of biaxial texture, coupled with evidence that biaxial texture improves with increasing film thickness, indicates that RHEED is a superior technique for probing surface biaxial texture.

Silicon wafers of p and n-types of 1 to 10 ohm-cm resistivity were implanted with nitrogen ions employing Plasma Immersion Ion Implantation (PIII) technique. Implantation were carried out at three doses corresponding to low (approximately 10¹³ /cm²), moderate (approximately 10¹⁵ /cm²) and high (approximately 10¹⁷ /cm²) dose regimes. Metal-silicon devices were fabricated using conventional semiconductor processing techniques. One set of the samples was annealed in forming gas ambient. Electrical characterization was done on all the devices. Change in reverse and forward current was observed with dose of implanted ions. The barrier height of the n- type sample decreases with increase in implanted ion dose, where as in the case of p-type silicon, barrier height was found increasing with dose. At high doses the top layer of both n and p-type silicon become nitrogen rich and exhibits optical properties different from that of unimplanted silicon as measured by ellipsometry. With the nitrogen rich layer, the device behaved like metal-insulator-silicon structure whose electrical characteristics have been studied. Sputtering effects of the nitrogen ions during implantation were also studied.

The dielectric properties of low-k material have been characterized using image-spectrum technique via Kramers- Kronig analysis. Quantitative analysis of experimental image-spectrum has been improved using two new quantitative methods. FFT interpolation and maximum entropy deconvolution were successfully used to solve the two problems: under- sampling and loss of energy resolution in image-spectrum technique, respectively. In this study, carbonated SiO₂ based low-k dielectric layer designed for copper metallization was used as a demo example. We show that the reconstructed image-spectrum obtained from ESI series images can be quantified with the same accuracy as conventional EELS spectrum. We also developed a new method to quantitatively determine dielectric constant for low-k materials. We have determined the thickness of the carbonated SiO₂ based low-k material using extrapolated thickness method from the materials of known dielectric constants. The dielectric function map can be deduced from 2-dimensional reconstructed single scattering spectra with providing the information of thickness via Kramers-Kronig analysis. We proposed a four-dimensional data presentation for revealing the uniformity of the energy dependent property. The accuracy of our methods depends on the thickness determination and on the quality of the reconstructed spectra from the image series. Finally, the dielectric property of carbonated SiO₂ based low-k material after annealed process was investigated using Kramers-Kronig analysis to found the relationship of dielectric constant and material density.

In this paper, application of scanning probe microscopy (SPM) and nanometer surface profiler of DEKTAK for determination of thermal stress in standard structure of QMIT is described. A three dimension finite element (3DFE) thermal stress simulator, a scanning probe microscopy measurements and nanometer surface profiler accompanied with a Peltier element (PE) have been used to determine the thermal stress distribution in the standard structure of QMIT. In this method by measuring and mapping the surface profile of Si-wafer around the embedded devices using SPM and DEKTAK the induced thermal stress is determined. Effects of different parameters such as baking temperature, power dissipation of the embedded GaAs-FET, geometry and elastic properties of thermal conductive epoxy have been described in details. Remarkable agreement between calculated and measured displacements created by thermal stress was found.

Microcantilevers are key components of many Micro-Electro- Mechanical Systems (MEMS) and Micro-Optical-Electro- Mechanical Systems (MOEMS) because slight changes to them physically or chemically lead to changes in mechanical characteristics. An inexpensive dual-fiberoptic microcantilever proximity sensor and model to predict its performance are reported here. Motion of a magnetic- material-coated cantilever is the basis of a system under development for measuring magnetic fields. The dual fiber proximity sensor will be used to monitor the motion of the cantilever. The specific goal is to sense induction fields produced by a current carrying conductor. The proximity sensor consists of two fibers side by side with claddings in contact. The fiber core diameter, 50 microns, and cladding thickness, 10 microns, are as small as routinely available commercially with the exception of single mode fiber. Light is launched into one fiber from a light-emitting diode (LED). It emerges from that fiber and reflects from the cantilever into the adjacent receiving fiber connected to a detector. The sensing end is cast molded with a diameter of 3 mm over the last 20 mm, yielding a low profile sensor. This reflective triangulation approach is probably the oldest and simplest fiber proximity sensing approach, yet the novelty here is in demonstrating high sensitivity at low expense from a triangular microstructure with amorphous magnetic coatings of iron, cobalt, permalloy, etc. The signal intensity versus distance curve yields an approximate Gaussian shape. For a typical configuration, the signal grows from 10% to 90% of maximum in traversing from 6 to 50 microns from a coated cantilever. With signal levels exceeding a volt, nanometer resolution should be readily achievable for periodic signals.

It is important to detect the metal fatigue in the steel. There are several known methods of detecting metal fatigue. However, there is a problem in which it is not the non- destruction and large equipment. We are investigating the method of metal fatigue by the laser induced thermal vibration. When the target absorbs a laser beam, the temperature gradient occurs in the surface and the back of the target. The steel is bent by this temperature gradient. When the intensity of laser is modulated, the target vibrates by the repetition of the bending. This method detects the metal fatigue from the variations of the amplitude vibration by material degradation, which is generated by the metal fatigue. It is non-destructive evaluation method and simple equipment. We succeeded in the detection of the metal fatigue by this method from the sample, which beforehand added the fatigue. In this paper, we compared the detection result with addition way of the fatigue. Then, effectiveness and features of this method were confirmed.

We have used the electrostatic self-assembly (ESA) processing technique to synthesize a series of functional nanocomposites. For example, such films exhibit large electro-optic coefficients (r₃₃), excellent piezoelectric properties (d₃₃), high electrical conductivity and giant magnetoresistance (GMR). By controlling the molecular structure of the components and the physical ordering of multiple multilayers, the macroscopic properties of the multilayer thin films fabricated using this simple, low-cost method may be determined. Such processing techniques may be incorporated with ink jet print technologies to form patterned thin film structures. For low-cost upscaling to larger substrates, spray techniques are being investigated.