The length and time scales of an atomistic simulation are often too small for any direct comparison with experimental observations. In order to study the coverage of pits (COPs) found on the Si (100) surface by epitaxial deposition, we first calculate rate of individual steps using molecular dynamics and then define a sequence of Monte-Carlo steps to study the effect of various factors on effective coverage of COPs.

The features of the correlated glancing scattering of medium energy ions by the imperfect surface of a single crystal have been investigated by computer simulation It has been shown that, from the correlation of the experimental and calculated energy distributions of the scattered particles, one may determine a spatial extension of the isolated atomic steps on the single crystal surface damaged by the ion bombardment. The presence of atomic steps on the surface lead to increase of the capture probability of channeling ions in the layers under the steps and to increase of probability of their dechanneling. The obtained computer simulation results show that dechanneled ions form characteristic peaks in the angular and energy distributions of scattered particles. Character of ions movement under the step (their ranges, energy losses and dechanneling) is determined both the grazing angle and capture angle under the step.

Physical Vapor Deposition (PVD) processes commonly lead to the formation of polycrystalline thin films due to the effects of island nucleation and growth. Scanning probe Methods such as Atomic Force Microscopy (AFM) or Scanning Tunneling Microscopy (STM) are widely used for the characterization of the film surface. The topographic data obtained from these measurements can be converted to roughness values, Power Spectral Densities (PSD's) or correlation functions.

It is the objective of this paper to evaluate the possibilities to characterize the polycrystalline template which generates the film surface solely by quantities derived from topographic data. For this purpose roughness values, PSD's and correlation functions of polycrystalline Al-Films deposited on glass substrates and from simulated surfaces are compared. The main factors which influence the shape of PSD's and correlation functions are determined and possible connections between the constitution of the polycrystalline template (e. g. shape and size-distribution of the crystalline domains) and the film roughness are discussed.

The nanoindentation behavior of DC magnetron sputtered 10 nm Cu and 10 nm Cu/2 nm Cr thin films deposited on Si (100) has been studied using a Hysitron nanomechanical system. X- ray diffraction and X-ray reflectivity were used to measure the film structure and film thickness, respectively. The grain size and orientation of Cu and Cu/Cr thin films were measured by TEM. Atomic force microscopy (AFM) was used to evaluate the surface morphology and roughness. At the same load, the nanoindentaion displacement of Cu/Cr is smaller than that for Cu, i.e., the 2nm thick Cr underlayer enhances the hardness of Cu. X-ray, TEM, and AFM results show that the grain size of Cu/Cr (< 15 nm) is actually larger than Cu (∼ 3 nm) indicating that the inverse Hall-Petch relationship may be operative.

Ru thin films were deposited on SiO2/Si and (Ba,Sr)TiO3 [BST]/Pt/TiO2/SiO2/Si substrates using Ru(C2H5C5H4)2 [Ru(EtCp)2] by metal-organic chemical vapor deposition (MOCVD). To determine the effects of the solvent, C4H8O [tetrahydrofuran: THF], it was injected into the reaction chamber by the Direct Liquid Injection (DLI) system while Ru(EtCp)2 was input through the bubbler system. Also, Ru thin films were deposited using a liquid source, Ru(EtCp)2 dissolved in THF, delivered by the DLI system. The surface of the Ru thin films deposited on the BST substrate using only Ru(EtCp)2 through the bubbler system was very rough and milky, but the addition of THF made the surface of the films smooth and clean. In addition, Ru films deposited at 325°C using Ru(EtCp)2 dissolved in THF through the DLI system have a dense and smooth microstructure with resistivity as low as 15µωcm.

The electronic structure of amorphous carbon nitride (a-C:H:N) thin films prepared by radiofrequency (rf) plasma decomposition of CH4/N2 mixture was determined by soft x-ray photoe1ectron spectroscopy by the mean of synchrotron radiation source. On increasing N2 fraction, the valence band shows profound changes. The new features are identified by a comparison of the experimental spectra with theoretically weighted density of the states of graphite and C3N4 structures.

X-ray scattering experiments on the homoepitaxial growth of Ag(001) Ag(111) and Cu(001) show that high vacancy concentrations can be achieved during low temperature deposition. It is observed that the vacancies, which can attain concentrations on the order of 2%, extend throughout the thickness of the deposited film. Moreover, vacancies are found to have a profound effect on the evolving morphology of certain surfaces, which is discussed in terms of prior studies of kinetic roughening in these systems.

In order to improve the performance and prolong the life of shape memory alloy material (SMA), it is very important to trace and study the microstructure change on the fatigue of SMA. The microstructure features between the samples before and after thermal fatigue (about 100,000 thermal cycles) of the NiTi-SMA films were examined and compared with each other by transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). It was found that there is no difference of microstructures between the two kinds of samples except some precipitates appeared in the fatigue specimen. These precipitates which may be identified as TiNi3 phase with a grain size of 10-20 nm may impede transformation from martensite to austenite which works as mechanism of SMA during thermal fatigue. Therefore, these precipitates result in the serious decay on SMA performance and further fracture of the SMA material.

The emergence of metal multilayers that exhibit giant magnetoresistance (GMR) has led to new magnetic field sensors, and approaches for nonvolatile random access memories. Controlling the atomic scale structure across the many interfaces within these multilayers is central to improve the performance of these devices. However, the ability to manipulate atomic arrangements at this scale requires an understanding of the mechanisms that control heterometal film growth during vapor deposition. It is important to develop methods that enable prediction of the effects of deposition conditions upon this structure. Atomistic simulation approaches have been combined with deposition reactor models to achieve this. We have applied these approaches to analyze the atomic scale structure of sputter deposited CoFe/Cu/CoFe giant magnetoresistive multilayers similar to those used for magnetic field sensing. Significant intermixing is revealed at the CoFe-on-Cu interface, but not at the Cu-on-CoFe interface. Recent experiments verified these predictions. The insights provide a basis for the development of processes that inhibit thermally activated atomic diffusion while allowing the controlled use of the metal atom impact energy and inert gas ions to manipulate the structure of interfaces.

Multifunctional structures are those that combine load bearing support in addition to supplemental functions such as actuation, electrochemical energy storage or thermal management. Electron beam - directed vapor deposition (EB- DVD) technology has been used for the deposition of templated cellular structures for micro heat-pipe structures and porous electrode coatings for rechargeable nickel - metal hydride cells. In addition to load bearing support, the tem- plated cellular structures exhibit enhanced thermal management characteristics and the electrochemical cells can be integrated into the load bearing supports of linear and truss based structures leading to their multifunctionality. Dur- ing EB-DVD, the electron beam evaporated vapor flux is encompassed by a rarefied transonic inert gas jet, entraining the vapor in a non-reactive gas flow and transporting it onto a polymer or metal template structure. Here, EB-DVD technology has been used to synthesize copper based templated cellular structures for thermal management systems and porous nickel coatings for the positive electrode of rechargeable nickel - metal hydride cells.

X-ray diffraction was used to measure the stress and the texture in thin molybdenum layers. The 500 nm thick layers were sputter deposited at various argon sputter pressures. All crystallites in the layers showed a strong tendency to develop a <110> direction perpendicular to the surface of the sample. Depending on the sputter pressure, a different fraction of the Mo crystallites developed a preference for a <110> direction parallel to the tangential direction of the rotating sputter table. The stresses found in the layer are best described when it is recognized that the crystallites in the layer belong to two groups: one group with both directions preferred and one group with only the out-of-plane direction preferred. For the intermediate sputter pressures the highest stresses were observed.

We used a previously reported kinematical electron scattering model1 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. In situ RHEED analysis reveals that the out-of-plane orientation distribution starts out very broad, and then decreases during IBAD MgO growth. Other results included evidence that the in-plane orientation distribution narrows, the grain size increases, and the film roughens as film thickness increases during IBAD MgO growth. Homoepitaxy of MgO improves the biaxial texture of the IBAD layer, making X-ray measurements of IBAD films with an additional homoepitaxial layer not quantitatively representative of the IBAD layer. Systematic offsets between RHEED analysis and X-ray measurements of biaxial texture, coupled with evidence that biaxial texture improves with increasing film thickness, indicate that RHEED is a superior technique for probing surface biaxial texture.

We have observed a distinct surface phase transition for an important class of colossal magnetoresistive materials, La0.65D0.35MnO3 (with D = Sr, Pb) occurring in a surface layer compositionally different from the bulk. The surface phase transition occurs around 240 K compared to350 K for the bulk and is fundamentally different. In the bulk, a ferromagnetic metal to paramagnetic ‘bad metal’ occurs, while the lower-temperature surface transition is from an n-type (in case of La0.65D0.35MnO3) or a p-type (in case of La0.65D0.35MnO3) semiconductor to a semimetal with increasing temperature.

Amorphous metal alloys are ideally suited for interconnects in micro-electromechanical sys- tems (MEMS) because of their resistance against stress- and electromigration, and their stability in chemically aggressive environments, which should both lead to a substantial improvement of lifetime and reliability of robust sensors. While amorphous refractory metal alloys and amor- phous silicides are excellent interconnect materials for devices operating at elevated tempera- tures, these systems lack the cost-effective and easy interconnect processing of the prevalent polycrystalline aluminum alloy metallizations. Amorphous aluminum alloys are applicable to devices operating at up to 200°C, and their stressmigration resistance and chemical stability is far superior to conventional polycrystalline aluminum alloys. These new metallizations are very promising for processing interconnects, in particular because of their high strength and ductility, though having low density, and their relatively low electrical resistivity compared to other amor- phous metal alloys. Therefore these metallizations are especially suited for surface acoustic wave (SAW) sensors, where the interconnects are exposed to considerable mechanical strains. In this work amorphous Aluminum Yttrium alloy thin film metallizations deposited on appropriate sub- strates at room temperature (R.T.) by ultra-high vacuum (UHV) electron beam evaporation will be presented, and their mechanical and electronic properties together with their temperature sta- bility will be investigated.

We studied the effect of carbon incorporation on the material and electrical properties of Ta2O5 thin film. We doped the Ta2O5 films with carbon using pulsed-dc reactive and rfmagnetron sputtering of Ta2O5 performed in an Ar/O2/CO2 plasma. In thick (70 nm) films, an optimal amount (0.8 - 1.4 at.%) of carbon doping reduced the leakage current to 10−8 A/cm2 at +3 MV/cm, a four orders of magnitude reduction compared to that in a pure Ta2O5 film grown in similar conditions without CO2 in the plasma. This finding suggests that carbon doping can significantly improve the dielectric leakage property at an optimal concentration. X-ray Photoemission Spectroscopy (XPS) analysis showed the presence of carbonate in these electrically improved carbon-doped films. Analysis by high-resolution transmission electron microscopy (HRTEM) exhibited no morphological or structural changes in these carbon doped films. Carbon doping showed no improvement in the leakage current in thin (10 nm) Ta2O5 films. This phenomenon is explained by a defect compensation mechanism, in which the carbon-related defects remove carriers at low concentrations but form a hopping conduction path at high concentrations.

There have been increasing interests in lithium rechargeable batteries, especially microbatteries, with rapid development of portable electronic equipments and MEMS(Micro electromechanical systems) technology. In this work, lithium manganese oxide, as a strong candidate for the battery materials, which is more abundant, stable in ambient state and less toxic than the other oxides such as lithium nickel oxides and lithium cobalt oxides, was deposited by rf magnetron sputter. The effect of thermal treatment on the microstructure and electrode characteristics of lithium manganese oxide cathode was investigated. In electrochemical experiment using liquid electrolyte, half-cell failure would be caused by manganese dissolution, degradation of electrolyte materials during charging/discharging process and so on. In this research we focus on interface reaction problem that would affect the cyclability and lifetime of microbattery. In order to reduce the interface reaction during operation, we introduce DLC(Diamond-like-Carbon) film that has high electrical resistivity, mechanical hardness and chemical stability. DLC film was deposited on sputtered lithium manganese oxide electrode by ECRCVD(Electron Cyclotron Resonance Chemical Vapor Deposition). DLC-top-layer LiMn2O4 film was more stable during charging/discharging reaction and higher discharge capacity in wide voltage windows than LiMn2O4 film.

Using amorphous Fe81B13.5Si3.5C2, Fe40Ni38Mo4B18, Fe66Co18B15Si1 and Fe72.6Cr22Al4.8Si0.3Y0.3 as model systems, we apply the laser-Mössbauer method in order to obtain metallic glasses with novel properties. As shown by transmission Mössbauer spectroscopy, the bulk magnetic texture was modified in a rational manner by applying a varying number of excimer laser pulses per spot (λ=248 nm, τ=8 ns). As shown by conversion electron Mössbauer spectroscopy, this process left the surface magnetic texture unchanged and induced a distribution of magnetic moment directions throughout the thickness of the foil. A similar dependence of the magnetic texture upon the number of applied laser pulses was obtained in metallic glasses irradiated with a Nd:YAG laser (λ=532 nm, τ=8 ns). However, in this case we observed the onset of surface crystallization in the hyperfine magnetic field distributions extracted from the CEMS spectra. When a pulsed alexandrite laser was used (λ=750 nm, τ=60 μs), the onset of crystallization was found to be accompanied by bulk oxidation and the formation of magnetite particles in the irradiated system. Finally, a crucial experiment was performed in order to demonstrate the role played by the magnetostriction constant in the onset of crystallization.

Semicontinuous metals films of copper and gold were grown on different substrates by pulsed laser ablation. The resistance and transmittance of these growing metal films were monitored in situ vs film thickness. Despite diverse experimental variations, it was found that both resistance and transmittance exhibited similar behaviors. Around percolation, the resistance exhibited a sharp drop whereas the transmittance exhibited a dip. In general, the onset of percolation depended on laser fluence and substrates. Under favorable conditions, metal films as thin as 1.5 nm would percolate.

Among the copper precursors used, cupric β-diketonate complexes exhibit a high sublimationrate and a low pyrolysis temperature. This work explored the possibility of using a nonfluorinated t-butylacetato complex of Cu(II) as the precursor. Secondary ion mass spectrometry and temperature-program desorption studies on the adsorption and decomposition of the ligand, tert-butyl acetoacetate (tBAA), of this precursor on Si(100) showed that at low doses, all tBAA molecules dissociated readily upon adsorption on the surface at substrate temperatures as low as –160°C. For dissociation through tBAA bonding via the ester oxygen to the surface, the bond scission occurring at the tBu-O bond resulted in the formation of surface tert-butylfragments, which in turn underwent a β-hydride elimination reaction to yield isobutene and surface hydride. In addition, the bond scission occurring at the tBuO-CO bond produced surface tert-butoxy specie, of which the hydrogen atom in the â position can be transferred to the oxygen atom of the butoxy group to yield isobutene and surface hydroxyl species. Its implication in the quality of the copper film generated is discussed.

We present a model for dislocation array image effects during epilayer island growth. Misfit dislocations often appear at an interface between phases, to accommodate a lattice mismatch. In many situations, such as early film growth, one of the phases may be discontinuous, leaving the interface region clearly bounded. The structure of such a finite interface differs from the normally-modeled infinite boundary because of end effects near the edges of the islands. We have modeled the dislocation structure of such a finite interface in MBE-grown InAs islands on GaP, and compare our results to high-resolution images of the same structure. The 11% misfit causes dislocation introduction from the outset of growth. Islands containing between 4 and 14 dislocations were examined, and dislocation spacings were found to be enlarged near the island perimeters. The model provides a clear understanding of this and other effects.