Stress-induced migration is one of the problems related to the reliability of metal interconnections in semiconductor devices. This phenomenon generates voids and disconnections in the metal interconnections. The purposes of this work are to establish the stress-induced model based on atomic migration and theoretically clarify the temperature characteristics of void formation and disconnection using the presented model. First, the stress-induced migration model based on atomic migration in which the driving force is the gradient of elastic potential is presented. Next, to clarify the temperature characteristics of stress-induced migration, the presented model is applied to the formation of voids and disconnections and the results of theoretical analyses are compared with experimental results. It was found that the temperature characteristics of the void formation show various patterns depending on the void interval, and the temperature characteristics of the disconnection show various patterns depending on the void interval and void radius. These theoretical results are in agreement with the experimental results.

The load-bearing capacity of self-lubricating W–S films can be improved by doping with nitrogen or carbon. In this study, the chemical composition, the atomic bonding, the structure, and the surface and cross section morphologies of sputtered W–S–C(N) films were analyzed. The addition of the doping element leads to a progressive broadening of the x-ray diffraction (XRD) peaks indicating a loss of crystallinity. In W–S–N films, amorphous structure could be obtained. In W–S–C films, W–C compounds were detected in conjunction with the hexagonal WS2 phase. For the highest C contents, a nanocomposite structure, including those phases and graphite, was suggested for the film. X-ray photoelectron spectroscopy results showed different types of bonds in the W4f peak in good agreement with the XRD results, i.e., when W–C(N) compounds were indexed W–S, W–C, and W–N bonds are present in the W4f peak. For the highest C content film, the detection of C–C bond in the C1s peak confirmed the formation of graphite.

The site-incorporation mechanism of M3+ dopants into A2+B4+O3 perovskites controls the overall defect chemistry and thus their transport properties. For charge-balance reasons, incorporation onto the A2+-site would require the creation of negatively charged point defects (such as cation vacancies), whereas incorporation onto the B4+-site is accompanied by the generation of positively charged defects, typically oxygen vacancies. Oxygen-vacancy content, in turn, is relevant to proton-conducting oxides in which protons are introduced via the dissolution of hydroxyl ions at vacant oxygen sites. We propose here, on the basis of x-ray powder diffraction studies, electron microscopy, chemical analysis, thermal gravimetric analysis, and alternating current impedance spectroscopy, that nominally B-site doped barium cerate can exhibit dopant partitioning as a consequence of barium evaporation at elevated temperatures. Such partitioning and the presence of significant dopant concentrations on the A-site negatively impact proton conductivity. Specific materials examined are BaxCe0.85M0.15O3-δ (x = 0.85 - 1.20; M = Nd, Gd, Yb). The compositional limits for the maximum A-site incorporation are experimentally determined to be: (Ba0.919Nd0.081)(Ce0.919Nd0.081)O3, (Ba0.974Gd0.026)(Ce0.872Gd0.128)O2.875, and Ba(Ce0.85Yb0.15)O2.925. As a consequence of the greater ability of larger cations to exist on the Ba site, the H2O adsorption and proton conductivities of large-cation doped barium cerates are lower than those of small-cation doped analogs.

Influences of the continuity of the matrix on Young's modulus and tensile strength of unidirectional SiC/SiC mini-composite prepared by the polymer impregnation and pyrolysis method were studied experimentally by observation of appearance of matrix and tensile test and analytically by a shear lag–Monte Carlo simulation. The continuity of the matrix was improved by the addition of particles such as ZrSiO4, barium magnesium aluminosilicate, and Pyrex (borosilicate glass) into the matrix. The improved continuity of the matrix led to the increase in stress carrying capacity of the matrix and therefore to the increase in Young's modulus and tensile strength of the composite. Such a correlation between the continuity of the matrix and the property of the composite was verified numerically by the shear lag–Monte Carlo simulation.

Room-temperature photoluminescence (PL) was observed at 1540 nm in erbium-implanted amorphous silicon carbide (a-SiC:Er) films grown by thermal chemical vapor deposition at 800 °C. The PL spectra of the a-SiC:Er samples did not exhibit any defect-generated luminescence, with the PL intensity at 1540 nm dropping only by a factor of 3.6 as the sample temperature was increased from 14 K to room temperature. Time-resolved PL measurements showed that the Er3+ luminescence lifetime of approximately 0.6 ms was nearly independent of sample temperature. In addition, luminescence quenching was observed as implanted Er dose exceeded 7 × 1015 ions/cm2. It is suggested that the lower density of Si and C vacancies in the stoichiometric a-SiC:Er, as compared to its non-stoichiometric a-Si1-xCx counterpart, along with the incorporation of a higher Er dopant concentration, can effectively quench defect-produced luminescence and lead to a significant improvement in PL performance. These properties indicate that stoichiometric a-SiC is potentially a viable candidate for optoelectronic devices operating in the 1540 nm region.

A technique has been developed to facilitate analysis of the microstructural evolution of solder bumps after current stressing. Eutectic SnPb solders were connected to under-bump metallization (UBM) of Ti/Cr-Cu/Cu and pad metallization of Cu/Ni/Au. It was found that the Cu6Sn5 compounds on the cathode/chip side dissolved after the current stressing by 5 × 103 A/cm2 at 150 °C for 218 h. However, on the anode/chip side, they were transformed into (Nix,Cu1-x)3Sn4 in the center region of the UBM, and they were converted into (Cuy,Ni1-y)6Sn5 on the periphery of the UBM. For both cathode/substrate and anode/substrate ends, (Cuy,Ni1-y)6Sn5 compounds were transformed into (Nix,Cu1-x)3Sn4. In addition, the bumps failed at cathode/chip end due to serious damage of the UBM and the Al pad. A failure mechanism induced by electromigration is proposed in this paper.

Dual cation (Yb + Y)-stabilized α-sialon ceramics with either stoichiometric composition or nonstoichiometric composition that yield less than 3 vol% of an additional intergranular liquid/glass phase were consolidated by spark plasma sintering (SPS). This process allows very fast heating and cooling, thus providing a unique possibility to monitor and manipulate the kinetics of phase transformation and grain growth during sintering. Below a temperature threshold, full densification and complete α-sialon formation are accompanied by very limited grain growth. The grain growth kinetics were investigated both by post heat-treatment of SPS pre-consolidated monophasic α-sialon bodies consisting of sub-micron sized equiaxed grains in a conventional graphite furnace using extended holding times (hours) and directly rapid annealing in the SPS apparatus above the temperature threshold (within minutes). Post heat treatment in the graphite furnace yielded in situ reinforced microstructures consisting of interlocking elongated grains only in the presence of an additional intergranular liquid/glass phase. Direct annealing by SPS process yielded in situ reinforced microstructures whether or not an additional liquid/glass was involved. The former microstructures are formed via the static Ostwald ripening mechanism whereas the latter ones are generated via a dynamic ripening mechanism. This demonstrates that the dynamic ripening provides an efficient means of developing in situ reinforced microstructure in α-sialon ceramics with improved mechanical properties.

Nanowhiskers and needle-like precipitates obtained by the liquid-liquid interfacial precipitation method for the systems of isopropyl alcohol and toluene solutions of C60 and (η2-C60)Pt(PPh3)2 were examined by transmission electron microscopy. Morphology of the C60 precipitates was remarkably changed by the addition of (η2-C60)Pt(PPh3)2 in the C60 toluene solution, and capsular needle-like crystals of C60 were formed. C60 cages were found to be directly contacted along the growth axis of (η2-C60)Pt(PPh3)2 needle-like crystals.

A novel deposition technique for the bio-functionalization by amine groups of surfaces of materials is presented. The process is based on the activation at high temperature of 3-aminopropyltrietoxysilane (3-APTS) molecules in vapor phase immediately before impinging on the substrate. Materials such as silicon, porous silicon, and titanium were chosen to demonstrate the validity of the process on surfaces with very different chemical properties. The effect of the activation process on the surface was evaluated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and x-ray diffraction (XRD). In addition, the reactivity under mild reaction conditions of the functionalized surfaces was determined by using a fluorescent reagent that specifically reacts with amine groups. From the experimental results it can be concluded that the proposed activation method induces amino-group fixation on the surface of materials, ranging from semiconductors to metals and insulating materials.

The microwave irradiation technique (MWIT) was applied to synthesize lithium manganese oxide having spinel structure using LiOH·H2O and ε–MnO2 as starting materials. The crystal and electronic structure depends on the irradiation time; x-ray diffraction patterns of the sample irradiated for 9 min were in good agreement with that of cubic structure without showing the peak of MnO2. The electronic structure of synthesized samples before and after lithium ion intercalation and/or deintercalation was investigated by Mn L-edge and O K-edge x-ray absorption spectroscopy.

Intermetallic compound (IMC) spalling from electroless Ni-P film was investigated with lead-free solders in terms of solder-deposition methods (electroplating, solder paste, and thin foil), P content in the Ni-P film (4.6, 9, and 13 wt% P), and solder thickness (120 versus .200 μm). The reaction of Ni-P with Sn3.5Ag paste easily led to IMC spalling after 2-min reflow at 250 °C while IMCs adhered to the Ni-P layer after 10-min reflow with electroplated Sn or Sn3.5Ag. It has been shown that not only the solder composition but also the deposition method is important for IMC spalling from the Ni-P layer. The spalling increased with P content as well as with solder volume. Ni3Sn4 intermetallics formed as a needle-shaped morphology at an early stage and changed into a chunk-shape. Needle-shaped compounds exhibited a higher propensity for spalling than chunk-shaped compounds because many channels among the needle-shaped IMCs facilitated Sn penetration. A reaction between the penetrated Sn and the Ni3P layer formed a Ni3SnP layer and Ni3Sn4 IMCs spalled off the Ni3SnP surface. Dewetting of solder from the Ni3SnP layer, however, did not occur even after spalling of most IMCs.

Nanoindentation of the reinforcement in a particulate reinforced metal matrix composite (PR MMC) enables direct investigation of reinforcement properties within the finished material. Mismatch between the elastic moduli of the reinforcement and matrix creates a “secondary indentation” effect, whereby the stiffer reinforcement particles themselves “indent” the more compliant matrix. A finite-element investigation was undertaken to quantify the additional penetration arising under secondary indentation for spherical and cylindrical particles. Modification of Sneddon’s equation for a flat punch by a scalar particle shape factor provided an accurate estimate of the additional penetration. The modified equation was combined with the analysis of Field and Swain to extract the particle elastic modulus from results obtained using a spherical indenter under a multiple partial-unloading indentation regime. The resulting methodology was used to determine the elastic moduli of silicon carbide particles and MicralTM microspheres in two aluminum-matrix PR MMCs.

Using cathodic arc plasma to deposit CrN on the steel has been explored and extensively studied to improve the wear and corrosion resistance of the steel structures. Metal vapor vacuum arc (MEVVA) source implantation is a novel and profitable surface-modification process coupled with the cathodic arc plasma. The effect of the MEVVA-implanted chromium on the corrosion behavior in form of Cr/steel, CrN/steel, and CrN/Cr/steel was evaluated in an aerated 0.1N HCl solution. The composition and structure of the MEVVA-implanted chromium and the cathodic arc plasma deposited CrN on steel were both examined by x-ray diffraction and transmission electron microscopy. The polarization resistance (Rp) of all samples was measured and compared with the results obtained from electrochemical impedance spectroscopy simulated by the equivalent circuit, to interpret the effect of MEVVA-implanted chromium on the corrosion mechanism of the CrN/Cr/steel. The corrosion products associated with the microstructures were analyzed by electron probe x-ray microanalyzer. The results indicated that the corrosion resistance of the CrN-coated steel was significantly enhanced by the MEVVA-implanted chromium in the CrN/Cr/steel assembly.

The photoluminescence (PL) and PL excitation spectra of the single-crystal samples of yttria-stabilized zirconia (YSZ) were measured. We found that the PL spectra of two samples for the 280-nm excitation significantly differ from one another in intensity, although the two samples have the same macrostructure and the same chemical composition. These results indicate that PL spectroscopy is a useful method for studying the microstructure of YSZ. The result of the trace-impurity analysis suggests that the large difference in PL intensity between the two samples can be explained by considering the influence of Nb in the YSZ sample. It seems that Nb in YSZ caused an yttria-associated defect. The broad emission band around 550 nm would be attributed to this defect. These results suggest that information can be obtained from its PL measurement not only on the yttria-associated defect, but also on the trace impurity in the YSZ.

The formation of U-type hexaferrites with the composition Ba4B2Fe36O60 (B = Co, Ni, Zn) was studied. Samples were characterized by means of x-ray diffraction, electron microscopy (with energy-dispersive spectroscopy), and thermogravimetric and thermomagnetic analyses. U-hexaferrites are formed from the intermediate phases M-hexaferrite (BaFe12O19) and Y-hexaferrite (Ba2B2Fe12O22), which at the same time represent units in the U-hexaferrites’ crystal structure. The preparation of monophase U-hexaferrites was made possible by combining high-energy milling or chemical coprecipitation with a calcination at 1250–1300 °C. Structural defects, such as stacking faults, were observed in monophase samples with a high-resolution transmission electron microscope. The observed defects can be regarded as seeds for the formation of other hexaferrite phases after prolonged calcination times or higher calcination temperatures.

The shear strength, intermetallic compound formation, and failure mechanism of high-lead solder (5Sn–95Pb) bump on flip chip under bump metallurgy, Al/Ni(V)/Cu, were investigated after thermal cycling, multiple reflow, and high-temperature aging. Two kinds of intermetallic compound, Cu3Sn and AlxNiy, were found at the interface. The Cu3Sn was formed between the solder and Ni(V) layer while AlxNiy was formed between Ni(V) and Al layer. The formation of the Cu3Sn compound will not affect the shear strength, 27–30 g, of the solder bump even after a high temperature long time aging test. However, the shear strength after the 30th reflow drops to less than 25 g, ascribed to the formation of a brittle compound, AlxNiy. The failure modes of the solder bump upon shear test were also discussed.

Using depth-sensing indentation, a pop-in phenomenon induced by grain boundaries, namely, a sudden indenter displacement jump when indented near a grain boundary segment, was observed in polycrystalline niobium. This grain-boundary type of pop-in occurs at a larger force than the initial elasto-plastic pop-in, which is observed with and without a grain boundary nearby. The experimental results show that this pop-in effect has a close relationship with the misorientation across the grain boundary. The occurrence of this pop-in phenomenon is rationalized in terms of slip transmission across the grain boundary.

A viscous-elastic-plastic indentation model was extended to a thin-film system, including the effect of stiffening due to a substrate of greater modulus. The system model includes a total of five material parameters: three for the film response (modulus, hardness, and time constant), one for the substrate response (modulus), and one representing the length-scale associated with the film-substrate interface. The substrate influence is incorporated into the elastic response of the film through a depth-weighted elastic modulus (based on a series sum of film and substrate contributions). Constant loading- and unloading-rate depth-sensing indentation tests were performed on polymer films on glass or metal substrates. Evidence of substrate influence was examined by normalization of the load-displacement traces. Comparisons were made between the model and experiments for indentation tests at different peak load levels and with varying degrees of substrate influence. A single set of five parameters was sufficient to characterize and predict the experimental load-displacement data over a large range of peak load levels and corresponding degrees of substrate influence.

The curvature of the loading curve, the initial slope of the unloading curve, and the ratio of the residual depth to maximum indentation depth are three main quantitiesthat can be established from an indentation load-displacement curve. A relationship among these three quantities was analytically derived. This relationship is valid for elasto-plastic material with power law strain hardening and indented by conical indenters of any geometry. The validity of this relationship is numerically verified through large strain, large deformation finite element analyses. The existence of an intrinsic relationship among the three quantities implies that only two independent quantities can be obtained from the load-displacement curve of a single conical indenter. The reverse analysis of a single load-displacement curve will yield non-unique combinations of elasto-plastic material properties due to the availability of only two independent quantities to solve for the three unknown material properties.

Fluorinated mesoporous organosilicate films were synthesized by sol-gel spin-coating on a quartz substrate using (heptadecafluorodecyl)trimethoxysilane, tetramethylorthosilicate, and n-cetyltrimethylammonium chloride as the fluoro-precursor, silica source, and supramolecular template, respectively. The photochromism efficiency of photochromic dyes (spiropyran) increases in the order non-porous < hexagonal mesoporous < fluorinated mesoporous organosilicate films. The relatively high efficiency of the photochromism of spiropyran in fluorinated mesoporous organosilicate films suggests that such films are promising materials for applications as optical shutters and light modulators.