Dislocation structures in Al-Cu thin films have been studied by transmission electron microscopy (TEM). We have observed that the contrast of interface dislocations disappears in the electron beam. We assume that the contrast dissolution is due to the spreading of the dislocation core at the crystalline/amorphous interface or due to a diffusive movement of the dislocation through the oxide. In any case, the relaxation is assumed to be controled by irradiation induced diffusion. As a consequence, the short range stresses and at least partly also the long range stresses of the dislocations relax. This relaxation changes the interaction force between dislocations and may thus significantly affect the mechanical properties of thin films. It is concluded that interaction between interface dislocations may not be responsible for the high temperature strength of aluminum films.

Experiments utilizing the creep properties of multilayer thin films to determine interfacial free energies are presented with essential theory. A new technique utilizing tubular multilayer foils is then described.

The relaxation of thermally induced strain in 500 nm thick polycrystalline Ag layers electron-beam deposited onto Si wafers was traced during ageing at room temperature. The layers consisted predominantly of matrix crystallites with {111} planes parallel to the surface and twin crystallites with {51 l} planes parallel to the surface. The macrostrain in the plane of the layer was determined from the X-ray diffraction line-profile position and the microstrain from the diffraction-line broadening. The residual macrostress relaxed from 160 MPa to 30 MPa in the matrix crystallites and from 170 MPa to 50 MPa in the twin crystallites. Simultaneously with the decrease in macrostress the microstrain decreases significantly for both texture fractions. The strain relaxation behaviour is governed by movement and subsequent annihilation of defects in the layer.

In this study, nanoindentation and nanoscratch testing were used to determine the effects of annealing and long term aging on the properties and fracture resistance of thin tantalum nitride resistor films on aluminum nitride substrates. These films were sputter-deposited to a thickness of 440 nm. Some films were left in the as-deposited condition while others were annealed or annealed and then aged. X-ray diffraction revealed that sputter deposition created high compressive residual stresses in the as-deposited films which were partially relieved by annealing. Subsequent aging of the annealed films had no effect on residual stress levels. Nanoindentation showed that mechanical properties were unchanged after annealing and after annealing and aging. However, nanoscratch testing showed that annealing markedly reduced the susceptibility to catastrophic failure with no further changes discernible after aging.

A multilayer consisting of parallel sided, elastically isotropic layers with thicknesses much smaller than their dimensions in the plane of the layers may develop large coherency stresses when the layers are thin enough. General formulae are given for the stress tensors in a flat periodic fully coherent multilayer which may contain any number of layers, each with different lattice parameters, elastic constants and thicknesses. As the thicknesses of the layers increase there is an increasing tendency for the interfaces to become incoherent thereby relaxing the elastic stresses, at the expense of creating higher energy interfaces between the layers. This tendency is particularly marked for unusually thick or unusually rigid layers or for layers with very large or small lattice parameters. Unlike the case of thin films on massive substrates, there is no single thickness at which coherency is lost. In this paper, the loss of coherency is explored by searching for energy minima in irregular multilayers.

The large thermal expansion coefficient mismatch between IV–VI semiconductors and silicon results in significant tensile strain when structures are cooled down following growth at high temperatures. Molecular beam epitaxy (MBE) growth of PbSe on Si (100) at 280°C on BaF2/CaF2 buffer layers results in high crack-density because of this strain. Interestingly, crack- free layers of PbSe can be grown by LPE on Si (100) by using MBE-grown PbSe/BaF2/CaF2 buffer layer structures. Unlike LPE-grown PbSe layers, however, a high crack-density was observed in Pbl-xSnxSe1-yTey layers grown by LPE on Si (100) using similar buffer layer structures. It is hypothesized that the addition of tellurium, which is known to increase IV-VI material hardness, inhibits plastic deformation and thus crack formation becomes the thermal strain relief mechanism. Ternary Pbl-xSnxSe layers grown by LPE exhibited much lower crack densities as compared to the quaternary layers and supported the conclusion that tellurium induced solid solution hardening occurs in the IV-VI materials system.

A comprehensive atomic-scale study is presented of the mechanical behavior of the InAs epitaxial film, the interfacial stability with respect to misfit dislocation formation, and the film surface morphology in InAs/GaAs(110) heteroepitaxy. If a GaAs buffer layer of ten-monolayer thickness is used in the epitaxial growth, a transition is predicted from a coherent to a semi- coherent interface consisting of a regular array of edge interfacial misfit dislocations at a critical film thickness of six monolayers. A second transition to a semicoherent interface consisting of a completely developed network of perpendicularly intersecting misfit dislocations is predicted at thicknesses greater than 150 monolayers. Our simulation results are in excellent agreement with recent experimental data.

Thin films of indium tin oxide, silica and chromium were deposited on the soda-lime-silica glass substrates with the thickness ranging from 50 to 2000 nano-meter. Their dynamic hardness were measured by the nano-indentation method with the indentation depth from 50 to 200 nano-meter. The hardness of indium tin oxide film increased and that of silica decreased with increasing film thickness. The hardness of chromium was almost constant regardless of film thickness. When the hardness of thin film was higher than that of substrate, the influence of substrate was greater compared with the reverse case. The dynamic hardness of engineering ceramics were about fifty percent higher than the ordinary Vickers hardness, but the ranking order was in good agreement. The Young's modulus from nano-indentation were a little higher than those by resonance method.

An indentation creep analysis has been performed to investigate micro-mechanical properties of amorphous nitrogen-containing carbon films. Using results of the slope of the time-displacement relation of creep procedure, the strain rate sensitivity exponent m is obtained. The m value of 0.004 was obtained for diamond-like carbon film without nitrogen. In contrast, those were found to be in the range between 0.009 and 0.101 for nitrogen-containing carbon films. These slightly increased with increasing the nitrogen content of the films. We present results that indicate that the nano-indentation creep technique enables clarification of the nano-structure of nitrogen-containing carbon films.

For several metallic systems, including tantalum, barrier (non-porous) oxide layers up to 200 nm thick can be grown quickly and efficiently using electrochemical techniques. The thickness of the oxide layer has been found to be linearly proportional to the voltage applied during the electrochemical growth process. These oxides can cause a substantial increase in both the hardness and wear-resistance of the surface. Ex-situ Micro and Nano indentation testing of the Ta/ Ta2O5 system has clearly shown that the indentation hardness increases with oxide thickness, even for indentation depths much greater than the oxide thickness. AFM imaging of indentations and analysis of nanoindentation curves suggests this increased hardness is due to the oxide impeding the pile-up of material at the edges of the indentation, which changes the geometry of the contact. Tribometer testing of various oxide thicknesses has shown that the oxide plays a similar role in preventing wear, specifically by preventing the transfer of material between the two contacting bodies and spreading the load over a greater area. Thus, the electrochemical growth of Ta2O5 provides a convenient method for providing protective hard coatings.

Thin film magnetic disks and head-sliders require protective overcoats, usually some form of carbon, to guard the magnetic elements against corrosion and wear and to provide long interface durability. The mechanical properties of these coatings are important for assessing their tribological performance. In this paper we present the results of nanomechanical properties of amorphous carbon (a-C) and nitrogenated carbon (CN) films deposited on Si(100). a-C and CN films were deposited on silicon by Facing Target Sputtering (FTS) technique. The elemental composition and bond characterization of a-C and CN films have been determined by X-ray Photoelectron spectroscopy (XPS). Nanoindentation experiments were performed using Hysitron Triboscope® in the load range of 10–200 μN, using a sharp 90° 3-sided pyramidal diamond tip ( 50 ± 10 nm radius). Hardness and Young's modulus of elasticity were determined from the load-displacement data. Nanowear studies were performed on the 10 and 20 nm a-C and CN films to determine the critical load. Below the critical load no significant wear is observed. Above the critical load however, the wear increases sharply. Abrasive wear seems to be the cause of the sharp increase in wear depth in case of a-C film. From the above observation, CN films exhibit excellent mechanical properties owing to its superior hardness property.

A method to obtain curves of elasto-plastic deformation of materials in depth-sensing indentation tests is proposed. Elasto-plastic deformation curves of thin films and brittle materials have been received at room temperature using this method.

The bulge test is an established method of measuring the residual stress and elastic stiffness of thin-film materials. We present an advanced experimental bulge-testing system that provides advantages in speed, accuracy, and flexibility. Key innovations include the use of a Laser Doppler Displacement Meter to measure deflection, an actuated air-cylinder mechanism to vary pressure, and sophisticated computer handling of data acquisition and analysis. A test case demonstrates that repeatability of results is extremely good.

For better understanding the mechanical properties of thin films it is helpful to use the same experimental methods as for bulk material, like tensile tests, thereby being able to directly compare the results. However, tensile tests of free-standing metallic thin films are often difficult to perform for reasons of preparation, handling, and stresses in the films. By leaving the metallic film on an elastic substrate tensile tests were performed in a rather simple and precise manner, using a commercial tensile testing machine. Stress-strain curves were determined by separating the force working on the substrate from that working on the film-substrate compound. Those measurements were done at room temperature for Al, AlCu(0. 5 wt %) and Cuo0.57Ni0.42Mn0.01 thin (200–2000 nm) films prepared by magnetron sputtering on 8 μm and 13 μm thick polyimide (Kapton) foils. The film microstructure was characterized by scanning and transmission electron microscopy and X-ray diffraction. The tensile strength of the fine grained films was found to be up to one order of magnitude higher than for the corresponding coarse grained bulk material. Al and AlCu films showed little, CuNi(Mn) films showed no plastical behavior. Crack formation started between 0.3 % and 2 % strain depending on the material, the thermal history, and the grain size.

Thermal processing steps in the production of packaged integrated circuits can lead to thermomechanical stresses. Additionally, the process of bonding wires to contact pads can lead to strain fields attributable to these. Synchrotron x-ray topography has been applied to packaged EEPROM Si ICs in order to produce maps of the strain fields induced by such processing steps. This technique allows for depth-resolved mapping with resolutions currently in the region of 5–10 μm throughout the entire mapping volume.

A comprehensive theoretical analysis is presented of the failure of metallic thin films due to electromigration-induced morphological evolution of transgranular voids. Fully self-consistent dynamical simulations emphasize the important effects on void dynamics of the surface diffusivity anisotropy, together with the strength of the applied electric field and the void size. The simulation results are discussed in the context of an approximate linear stability theory. Our simulations predict formation of wedge-shaped voids, as well as failure due to propagation of slit-like features emanating from void surfaces, in excellent agreement with recent experimental observations.

A two-dimensional void nucleation model in thin-film metal interconnects is proposed. The model is based on the evolution of stress and deformation fields obtained from numerical modeling. Interface flaws between the metal and the surrounding dielectric are assumed to exist. A unique pattern of shear stress resolved on the slip systems of the metal is found. A model of dislocation slip is constructed in accord with the evolution of the shear mode. The mechanism of crystallographic slip is such that lateral thinning of the metal line at the debond region, together with the slip steps produced at the edges of debond lead to a net transport of atoms away from the interface defect, and a physical void is thus formed.

A study has been conducted on ZrC/VC alloy thin films prepared by both pulsed laser deposition (PLD) and RF magnetron sputtering. The phase formation, wear properties, and hardness of these thin films were examined. An alloy target comprised of 36% VC and 64% ZrC (atomic %) was used to deposit films at 200°, 2000°, and 400° C. The nominal film thickness was 0.6 μm. X-ray diffraction (XRD) analysis revealed these films were solid-solution alloys and showed a preference for (100) orientation for sputter-deposited films and a (110) orientation for laser deposition. More highly oriented films were obtained at elevated temperatures as evidenced by rocking curve measurements on the PLD films. The FWHM of the peaks ranged from 2.2° to 8.3° for films deposited at 400° C and 20° C, respectively.

Using time-of-flight quadmpole mass spectrometry (TOFQMS), we performed plume diagnostics to measure particle energies and the thermalization effects of the background gas. In vacuum, typical ion energies ranged from ˜5–100 eV while the neutral atoms had kinetic energies from ˜1–5 eV. Our measurements show that the background gas can be used to selectively thermalize low mass components in the plume. From measured kinetic energies and collision effects of the gas, the changes in crystallographic structure of the alloy with pressure appear to result from collision-induced effects from condensation of the Zr atoms. This ‘heavy’ atom effect may be an important new processing parameter with which to adjust film morphology and crystal texture.

The surface of a cemented carbide was modified using a KrF pulsed laser process to achieve a microrough structure, leading to stronger adherence of diamond films to cemented carbide substrates. The surface morphology and roughness were investigated with laser conditions. After the surface modification with the laser and the etching of the modified surface, heat treatment was performed prior to deposition of diamond film in order to observe changes in surface morphology and adhesion. Diamond films were grown by chemical vapor deposition process. The results indicated that the heat treatment of the modified cemented carbide improved the adhesion of diamond films by the recrystallization of tungsten carbides into the fine and long grains. As laser energy for the modification of a cemented carbide increased, the surface roughness increased and tungsten carbide (WC) was transformed to WC1−x(X =0–0.3) and then to W2C.

The technique of differential gas pressure calorimtery is used to simultaneously measure heat and work of isothermal deformation of acrylic based latex blend coatings. These coatings comprise of phase separated hard and soft components resulting in a combination of stiffness and toughness. An overall energy balance approach is adopted to study the partition of energy between the two phases in their respective energy-dissipating and energy-absorbing mechanisms. The toughness is maximized by a simultaneous maximization of heat dissipation and energy absorption; a fact often overlooked in the design of commercial rubber toughened systems that focus almost entirely on increasing the energy absorbing capacity of the glassy matrix. It is observed that maximizing both the energy absorption as well as dissipation can result in much higher toughness without a large sacrifice in stiffness.