Nanocrystalline copper/hydrogenated amorphous carbon films have been deposited on Si substrates at the floating potential using a distributed electron cyclotron resonance microwave plasma reactor. In this deposition technique, the microwave plasma-enhanced chemical vapor deposition process of carbon from argon-methane or argon-acetylene mixtures of various compositions was associated with the sputter deposition of copper from a copper target. The total pressure was fixed at 0.13 Pa. For deposition, the substrates mounted on a water-cooled substrate holder were maintained at ambient temperature. The composition of films determined by Rutherford backscattering spectroscopy, energy recoil detection analyses and nuclear reaction analyses was investigated as a function of the gas phase composition. The structure of films was identified by X-ray diffraction (XRD) techniques and the size of copper crystallites incorporated in the amorphous carbon matrix was deduced from XRD data. The magnitude of residual stresses developed in these films was calculated from the radius of curvature of film/substrate samples determined by profilometry. The residual stress values were found to be nearly independent on the composition of films and deposition parameters.

Using density functional theory and the full-potential linearized augmented plane wave (FLAPW) method, we investigate the formation and stability, and atomic structure, of rocksalt AlN/TiN and AlN/VN systems, including properties of the clean surfaces of the constituent materials. Calculations of the adlayer formation energy highlights the effect and interplay of the various energetic contributions on the growth of these strained systems, where the so-called “surface-interface” interaction energy is found to be important for the initial stages of AlN epitaxy. A significant strain energy builds up for increasing number of layers, where it is greater in the AlN/TiN system, which limits the thickness of rocksalt AlN regions that can grow before a structural transition to the lower energy wurtzite phase takes place. From our calculations, together with the known experimental critical thicknesses, we can obtain an accurate estimate of the wurtzite/substrate interface energy. That these values are high explains why the metastable rocksalt phase, which has significantly lower interface energies, is stabilized.

We have used a recently developed x-ray structural microscopy technique to make nondestructive, submicron-resolution measurements of the deformation microstructure below a 100mN maximum load Berkovich nanoindent in single crystal Cu. Direct observations of plastic deformation under the indent were obtained using a ∼0.5 μm polychromatic microbeam and diffracted beam depth profiling to make micron-resolution spatially-resolved x-ray Laue diffraction measurements. The local lattice rotations underneath the nanoindent were found to be heterogeneous in nature as revealed by geometrically necessary dislocation (GND) densities determined for positions along lines beneath a flat indent face and under the sharp Berkovich indent blade edges. Measurements of the local rotation-axes and misorientation-angles along these lines are discussed in terms of crystallographic slip systems.

A novel in-situ electrical characterization technique is used to study the deformation behavior of silicon during nanoindentation. The method involved the formation of a Schottky contact on high resistivity epitaxial Si that is converted to an ohmic contact when Si transforms from the familiar semiconducting Si-I to a metallic Si-II phase. This behavior leads to substantial changes in the current measured across the sample. The Si conductivity used (epitaxial 5 Ωcm on 6 × 10-3 Ωcm) provides particular sensitivity to the onset of a phase transformation directly under the indenter. On unloading, a reverse transformation from ohmic to Schottky contact was observed. This configuration was used to correlate the observed changes in the electronic properties with features in nanoindentation load-unload curves. The onset of the transformation to the metallic phase was observed to occur during loading using both spherical and Berkovich indenters. Interestingly, the onset of the transformation was detected before the observed discontinuity on loading (the so-called ‘pop-in’ event). This observation is consistent with our previous suggestion that the pop-in event is a result of the onset of flow of the ductile metallic phase beyond the constraint of the indenter. These changes were consistently observed after repeated indentation on the same position in the sample, indicating that small volumes of Si-III and Si-XII crystalline phases as well as amorphous Si (a-Si), which form on unloading, can transform back to the metallic Si-II phase on reloading. A strong decrease in the measured electrical current across the sample occurred as soon as the unloading cycle commenced and prior to the observation of the pop-out event. Overall, these in-situ measurements have provided much insight into pressure-induced transformation in Si under nanoindentation.

A new in-situ surface observation system under tensile stress with an atomic resolution has been developed for the purpose of the explanation of the deformation of the surface and the crack growth mechanism for thin films in the micro- and nano-mechanical systems. The mechanical properties such as Young's modulus can be determined at the same time. This observation system consists of the on-chip tensile testing system and a commercialized atomic force microscope (AFM). The on-chip testing system is characterized by a static loading mechanism with a flat spring and a test chip of single-crystal silicon of 15×15×0.5 mm. Particular attention has been paid to the suppression of the vibration which effects on images of the surface with an atomic resolution. Atomic images of the surface of mica can be observed under various tensile strains till the occurrence of the fracture. The growth of the cracks and Young's modulus for TiN thin film deposited on silicon (100) specimen can be also clarified.

Quasicrystalline precursor coatings were deposited on single crystal silicon and sapphire wafers by RF sputtering from an AlCuFe powder composite target. Synchrotron white beam radiography/topography and stress analysis were performed in situ on the wafers during heating to 495 or 585°C, and subsequent cooling. A plateau region of constant stress was present throughout most of the 1 hour anneals before a large tensile stress developed in the film during cooling due to coefficient of thermal expansion mismatch. Cracking was observed for films on both substrates at an average film stress of approximately 930 MPa. Distinct differences in the fracture behavior were observed for the two different substrates. X-ray diffraction performed on films after annealing suggested that texturing took place during the transition to a fully developed quasicrystalline structure.

The present work is concerned with the analysis of elastic unloading data in conventional methods of analysis of nanoindentation test data. Experimental and finite element results are used to show that the reloading of a residual impression with and without the presence of residual stress is an elastic event, and further shows that the estimation of modulus and hardness computed using established techniques is in error due to the assumption the sides of the residual impression are straight. This work calls into question the validity of commonly used methods of test and analysis of instrumented indentation test data that use the elastic unloading data as the basis for the calculation of modulus and hardness of the specimen material.

In a previous paper, it was shown that the tribological properties of NbxNy thin films produced by ion beam assisted deposition (IBAD) depend strongly on the beam energy and the ion-to-atom (R) ratio. This study was designed to separate ion energy vs. ion momentum effects on film stress, crystalline phase, grain size, morphology, and composition, all of which influence the tribological properties of the films. Inert ion beams (Kr, Ar, and Ne) were used in conjunction with a nitrogen gas backfill to independently control ion energy and ion momentum transfer to NbxNy films. The ion species, energies, and R ratios were chosen to create a matrix of coatings that exhibited the same total energy deposition with different momentum transfer or the same momentum transfer but different total energy deposition. The resultant films were characterized using Rutherford Backscattering Spectroscopy (RBS), x-ray diffraction (XRD), atomic force microscopy (AFM), and residual stress analysis. Crystalline phases and texture, as well as residual stress, were more closely correlated with ion momentum transfer to the coating atoms than with overall ion energy input.

We have evaluated the hardness and elastic properties of thin films by using a simple procedure to calibrate the tip shape effect of the nano-indentation data. For the simplification, a truncated-shape approximation and linear fit are used to estimate the tip-shape and contact stiffness, respectively, substituting for polynomial area-function and power-law fit. The parameters used in the correction were determined by a fused silica and a single crystal silicon (100) surface. Different film/substrate systems are designed in order to assess these fitted parameters used in the correction. The transition behavior observed from the film to the substrate is well coincide with the other film thickness results, where the indentation depth above 50nm.

Amorphous CNx thin films were deposited by pulsed laser deposition (PLD) combined with a nitrogen rf radical beam source which supplies active nitrogen species to the growing film surface. The deposited films were characterized by X-ray photoelectron spectroscopy (XPS), Raman scattering, and Fourier transform infrared (FTIR) spectroscopy. Nitrogen content of the deposited films increased with increasing rf input power and N2 pressure in the PLD chamber. The maximum N/C ratio 0.23 was obtained at 400 W of rf input power and 1.3 Pa. XPS N 1s spectra shows the existence of several bonding structures in the deposited films. Electrical properties of the deposited films were investigated. The electrical conductivity decreased with increasing N/C atomic ratio. Temperature dependence of electrical conductivity measurements indicated that electronic conduction occurred by variable-range hopping between p electron localized states.

Although slow and dissipative, sputtered thin-film shape-memory alloys like equiatomic titanium-nickel can exert a large ohmically-excited force displacement product when deployed in photolithographically micromachined actuators. They give energy densities far exceeding those typically produced by competing microactuator materials [1], and their size can probably be scaled down to the nanometer range (where the benefits of high surface to volume ratio are best exploited for speed and efficiency). But a large, energetic, and resettable actuation stroke is possible only if some agency has imparted a non-trivial initial plastic strain, of between one and five percent, to the martensite phase. Is not always obvious how this strain is to be achieved when discrete mechanical manipulation of the active element is difficult. Furthermore, for cyclic actuation, a resetting-force that periodically re-deforms the martensite during the cooling interval must arise naturally from mechanical elements in the design. Here, several methods responding these requirements are discussed in relation to various kinematic themes.

A combined numerical and experimental study was undertaken to investigate the effect of microstructural heterogeneity on indentation response. Finite element analyses were carried out to simulate the stress-strain behavior and the indentation response of two model heterogeneous systems: one with hard particles embedded within a soft matrix and the other with a pore-containing ductile material. For the particle-containing system, the indentation response consistently overestimates the overall strength of the composite. This is largely due to the localized increase in particle concentration directly underneath the indent. For the porous system, the indentation response consistently underestimates the overall strength due to the pore-crushing effect. Experiments on metal-ceramic composites confirmed the non-correspondence between the indentation and stress-strain responses, even when the indent size is much greater than the microstructural feature size. Implications of the present findings in utilizing indentation to quantify surface mechanical properties are discussed.

Novel superhard wear resistant nanocomposite coatings nc-(Ti1-xAlx)N/a-Si3N4 for advanced machining tools were developed and introduced into large scale industrial production within a relatively short time. We describe the development of the coating technology based on vacuum arc evaporation from a specially designed cylindrical cathode and, as a result of that development, the improvement of the properties and machining performance of the coatings.

The structural, mechanical and tribological properties of MoS2/metal and MoS2/carbide multilayer thin films have been examined in this study. The films were deposited by pulsed laser deposition of sequential layers of MoS2 and either Ti, Cr or TiC. The compositions of the films were analyzed by wavelength dispersive spectroscopy (WDS) and confirmed the presence of the deposited elements. X-ray diffraction and cross-section SEM methods were employed to characterize the films. The XRD results did not reveal the presence of separate Ti, Cr or TiC phases, and the SEM did not show any multilayer structures. From these results, it was concluded that the added metal or carbide elements are present as either a dispersed nano-structured phase or in solid solution with the MoS2. Nonetheless, friction and wear testing showed dramatic improvements over MoS2 films when tested in a humid (45% r/h) environment.

Ultra low-k materials used in Cu damascene process are inherently soft and weak in nature; hence the evaluation of tribological properties of these materials is an issue of paramount importance in the field of semiconductor fabrication. Chemical Mechanical Polishing (CMP) of these films is a major challenge due to their reduced modulus and cohesive strength. The objective of this research is to develop a strong understanding of the tribological properties of Cu ultra low-k dielectric materials for successful implementation in the semiconductor devices. The Cu ultra low-k systems are polished at different conditions of load and platen rotation and their polishing behavior is compared with the standard Cu-SiO2 system. The polishing behavior of Cu and the barrier Ta material is studied in order to effectively detect the end point of the Cu CMP process. Delamination studies, post process surface characterization using scanning electron microscopy and the reliability issues of these materials also come within the scope of this study.