We have studied the isothermal relaxation behavior of 500 nm Cu films with SiNx passivation and barrier layers on Si substrates. Oxygen content in the Cu films was varied by deposition in various oxygen partial pressures in the range 10-10 to 10-4 Torr. The substrate curvature method was used to investigate the thermomechanical behavior of the Cu films. Isothermal relaxation experiments were performed in the temperature range 50-175°C. Comparison with constitutive creep deformation equations shows that the relaxation data in this temperature range are well described by power law behavior. Under certain isothermal conditions related to temperature, stress, and thermal history, anelastic recovery was observed– i.e. while in a tensile stress state and with the temperature held constant, the overall film stress was seen to increase over a relatively short time scale.

The effect of hot isostatic pressure processing (HIP) on MnAl films has been compared to vacuum annealing for the purpose of obtaining substantial amounts of tau phase MnAl in films under 200 nm. Films were deposited by dc sputtering from both MnAlNiC an MnAl targets. As-deposited films were nearly amorphous. Post deposition annealing in vacuum produced only small amounts of the ferromagnetic tau-phase in films thinner than 200 nm.

In all instances, regardless of substrate and sputtering target, the use of HIP in place of vacuum annealing increased the degree of crystallinity of the samples when compared to those annealed in vacuum. For the 100 nm samples deposited from the MnAlNiC target, these changes in crystallinity were accompanied by changes in the M-H loops of the samples. MnAlNiC HIP samples had improved magnetic properties compared to those of equal thickness annealed in vacuum. The 100 nm HIP sample sputtered from the MnAl target also showed an increase in moment, though the changes were not as dramatic as those seen in the samples sputtered from the MnAlNiC target.

The 50 nm films from both targets also showed a change in crystallinity when compared to vacuum annealed samples. These films, unlike the 100 nm films, had ferromagnetic properties that were no better than those of the vacuum annealed samples. This suggests that while the 2 kbar of pressure used in this study assists in the formation of tau-phase in 100 nm films, the appropriate pressure for forming tau-phase in 50 nm films is yet to be determined.

Positron Beam Analysis was for the first time performed in combination with a four-point bending stage. Applications of this novel technique on PVD TiN (5 m thick), WC:H (2.5 m) and CrN (1.5 m m) layers on tool steel, low carbon steel and stainless steel substrates are discussed. It appeared from PBA results that for these systems the coatings did not fail by delamination during bending. SEM confirmed that there was no decohesion but instead, cracking of the coatings was observed. In order to weaken the interface and quantify adhesion properties we propose to induce blistering based on localised gas implantation.

A Membrane Deflection Experiment was used to test the mechanical response of freestanding thin film gold specimens. We present stress-strain curves obtained on films 0.3, 0.5 and 1.0 μm thick. Elastic modulus was consistently measured in the range of 53-55 GPa. Several size effects on the mecha nical properties were observed including yield stress variations with membrane width and film thickness. It was observed that thickness plays a key role in deformation behavior with a major transition in the material inelastic response occurring between a thickness of 0.5 and 1.0 μm. The size effects here reported are the first of their kind in the sense that the measurements were performed under a macroscopically homogeneous axial deformation, i.e., in the absence of macroscopic deformation gradients.

Nanoindentation test techniques were combined with deposition of highly stressed overlayers to study the interfacial fracture susceptibility of gold-on-copper and gold-2w/o-copper alloy films. The gold-on-copper film blistered readily following deposition of stressed tungsten overlayers. Additional stress from nanoindentation was required to trigger delamination and blister formation in the gold-copper alloy film. Fracture energies were then determined using mechanics-based models. The results show that the gold-copper alloy exhibited higher fracture energies than the gold-on-copper films. This increase scaled with film strength suggesting that the higher measured fracture energies in the gold-copper alloy film were due to solid solution hardening.

Depth sensing nanoindentation and nanoscratch testing were combined with atomic force microscopy (AFM) and electron microscopy observations to study mechanical properties and fracture behavior of a number of TixAl1-xNyC1-y hard thin films. Various failure modes were activated either by normal loading-unloading or by microscratching of the samples to provide an estimation of the fracture toughness and interfacial fracture energies. By changing chemical composition and deposition conditions various nanostructured thin films including monolitically grown single layer, nanocomposite, and multilayers were coated onto the tungsten carbide-cobalt substrates. All tested films exhibit elevated mechanical properties with high hardness (38 – 45 GPa) and modulus (500 – 570 GPa). Under sufficiently high load indentation the formation of corner Palmqvist type radial cracks were usually observed because of small modulus mismatch between coating and substrate, good adhesion, and in particular high toughness of both substrate and films in spite of great difference in their respective hardness. Various failure modes were activated and the sequences of fracture events were determined using stepwise or continuously increasing load scratch tests. Some other films were found to be more sensitive to tensile stress behind the indenter which generates regularly repeated microcracks on the scratch track. Other films in particular multilayers were appeared more susceptible to compressive stress ahead of the indenter leading to local delamination at the interface between layers and the formation of irregular microcracks under the contact zone.

The coordination of the carbon atoms in the diamond-like carbon (DLC) films formed by Ar gas cluster ion beam (GCIB) assisted deposition of fullerene was investigated using synchrotron radiation. Near-edge x-ray absorption fine structure (NEXAFS) spectra of the carbon K-edge of the DLC films formed by various methods were measured over the excitation energy range 275-320 eV, using synchrotron radiation. On the basis of the analysis of the peak corresponding the transition of the excitation electron from carbon 1s orbital to Φ orbital, relative sp2 contents of various DLC films were determined. The DLC films formed by Ar GCIB assisted fullerene deposition were found to consist of a high sp3 hybridized carbon.

In this study of thin film plasticity, the relationship between thermomechanical behavior and dislocation motion has been investigated in copper constrained by a silicon substrate. The stress-temperature behavior as determined from wafer curvature experiments has been directly compared to deformation microstructures observed during in situ thermal cycling of plan-view specimens in the transmission electron microscope. The flow stress of copper films with thicknesses ranging from 100 nm to 400 nm was found to be constant, indicating that strengthening mechanisms may be saturated in this thickness regime. Moreover, unexpected dislocation glide on a plane parallel to the film surface, which should experience no resolved shear stress, provides potential evidence for the occurrence of constrained diffusional creep in a 270 nm film.

The well-known grain-interaction models for the description of the macroscopic elastic behaviour of polycrystalline specimens, for example the models due to Voigt and Reuss, may be applied to bulk specimens, but they are generally not suitable for thin films because they imply macroscopic elastic isotropy of the body. A thin film is usually at most transversely elastically isotropic, even in the absence of texture. A recently elaborated, alternative model for grain-interaction in thin films, adopting grain-interaction assumptions first given by Vook and Witt (J. Appl. Phys. 7, 2169 (1965)), is able to predict the transversely isotropic elastic behaviour. Although this model is more appropriate for thin films than traditional models, it still imposes extreme grain-interaction assumptions, which are in general not compatible with the true elastic behaviour of real specimens. In this paper a more general approach to grain-interaction in thin films is proposed.

In this work, NiAl films deposited by magnetron co-sputtering onto silicon substrates with compositions between 45.0 and 51.5 at-% Al and a thickness of 1.2 μm were studied. The films exhibited grain sizes comparable to the film thickness. Furthermore, the films were found to have fiber textures with the strongest component being (110) for the very Ni-rich and (111) for the stoichiometric and Al-rich films. The residual stresses in the Ni-rich and stoichiometric films after annealing were found to be independent of composition, while the Al-rich films showed a significant decrease in film stress. This stress drop can be related to severe cracking in the Al-rich films, which has not been observed in the stoichiometric and Ni-rich films, indicating that the fracture toughness depends on composition. Based on a simple estimate, the fracture toughness of these Al-rich films was determined to be in the range of 1 to 2 MPa m-1/2, which is somewhat smaller than commonly reported bulk values for polycrystalline NiAl.

We present results from a study of the vibrational, structural, and electronic properties of C60 powder and thin films. Raman spectroscopy and diamond anvil cell have been used to study pressure dependence of the Raman active modes of C60 powder. The material undergoes structural phase transition between 9 and 15 GPa. Some of the Raman modes soften, while others harden with increasing pressure. Thin films of C60 and La-doped C60 have also been studied by using Raman scattering, x-ray diffraction, x-ray photoelectron spectroscopy and uv photoemission spectroscopy. Whereas the powder and La-doped C60 films exhibit fcc crystalline structure, the C60 film appears disordered. Further, we observe a significant difference in the electronic valence bands of the doped and undoped films.

Thin films of gold can be grown on {001} Ge single crystal substrates in two equivalent {110} orientation variants, related to each other by a 90° rotation about the surface normal. The morphology of the films is that of a mazed bicrystal, a polycrystalline film with many randomly distributed columnar grains in only two orientations. All grain boundaries are of the type S99 and display pure tilt character. In this work, we report on observations of the structural relaxation of these grain boundaries, with special emphasis on their characteristic behavior at the intersection with free surfaces and their evolution during thermal annealing.

The mechanical properties of freestanding electroplated Cu films were determined by measuring the deflection of Si-framed, pressurized membranes. The films were deformed under plane-strain conditions. The pressure-deflection data are converted into stress-strain curves by means of simple analytical formulae. The microstructure of the Cu films was characterized using scanning electron microscopy and x-ray diffraction. The yield stress, Young's modulus, and residual stress were determined as a function of film thickness and microstructure. Both yield stress and Young's modulus increase with decreasing film thickness and correlate well with changes in the microstructure and texture of the films.

The effect of residual stress on the out-of-plane deflection in a free-standing thick diamond films was investigated theoretically and experimentally. The deflection is believed to be caused by the variation in residual stress with film thickness. Key idea of this study is that the stress variation may be produced by gradually increasing substrate deformation resulting from the layer-by-layer deposition of the film. The layer-by-layer deposition was modeled by using infinitesimal plate-bending theory, considering the two deformation modes of contraction or expansion and bending. To verify the suggested model, several hundred micron thick diamond films were fabricated on Si, Mo and W substrates of varying thicknesses by microwave plasma assisted chemical vapor deposition. The model's predictions on bowing, based on intrinsic stress value measured by the curvature method, were in good agreement with the experimentally measured curvature of the as-released films. Finally, it is concluded that the bowing of CVD thick films depends on the intrinsic stress variation of the film associated with gradual increase in substrate deformation.

Two plasma-enhanced chemical vapor deposited (PECVD) dielectric films pertinent to microelectronic-based applications were examined for thermo-mechanical stability. Both films–silicon nitride and silicon oxy-nitride–showed significant permanent non-equilibrium changes in film stress on thermal cycling and annealing. The linear relationship between stress and temperature changed after the films were annealed at 300°C, representing a structural change in the film resulting in a change in coefficient of thermal expansion and/or biaxial modulus. A double-substrate method was used to deduce both properties before and after the anneal of selected films and the results compared with the modulus deconvoluted from the load-displacement data from small-scale depth-sensing indentation experiments.

We have studied the mechanical and magneto-optical properties of postdeposition oxidized Co thin films. Oxidization process leads to the formation of double-layered structure of cobalt oxide on top of metallic cobalt. The nanoindentation measurements show decrease in hardness and Young's modulus at low annealing temperature and are related to increasing porosity of the film. The magneto-optical Kerr effect (MOKE) reveals dependence of the MOKE spectra on annealing temperature. The increased coercivity of the annealed films has been observed by MOKE and is related to the structure of the film.

Widely accepted model of bending of a single crystal suggests that edge dislocations are introduced from both the compressed surface and extended surface. The present study examined this model by molecular dynamics using an embedded potential. Shockley partial dislocations are created on the compressed surface. Due to the characteristics of inter atomic potential, the stress on the compression surface is higher than that on the extended surface.