Pore sealing has become a critical issue for the implementation of porous low-k dielectrics and for realizing acceptable reliability performance of the interconnect. This study focuses on fabrication of ultra-thin, conformal and plasma resistant pore seal layer and on understanding parameters playing a role in sealing the surfaces of porous low-k films. It was found that 2.5 nm-thick pore seal layer shows a perfect toluene seal property for the porous low-k film whose pore radius is 1.48 nm. The pore seal layer still show a good toluene seal property after irradiation of He plasma at 250°C for 10 sec. The increments of dielectric constant by applying the pore seal layer and by the He plasma irradiation for 10 sec are 0.04 and 0.03, respectively. Interestingly, all of toluene seal property, refractive index of the bottom part of the film and dielectric constant started to deteriorate after irradiation of He plasma for 20 sec. It was suggested that when toluene seal property degrades, plasma would start diffusing into pores and both refractive index of the bottom part of the film and k value start to increase.

Multifunctional polymer-based biomaterials, which combine degradability and shapememory capability, are promising candidate materials for biomedical implants. An example is a degradable multiblock copolymer (PDC), composed of poly(p-dioxanone) (PPDO) as hard and poly(ε-caprolactone) (PCL) as switching segments. PDC exhibits a unique linear mass loss during hydrolytic degradation, which can be tailored by the PPDO to PCL weight ratio, as well as an excellent thermally induced dual-shape effect. PDC can be synthesized by co-condensation of two oligomeric macrodiols (PCL-diol and PPDO-diol) using aliphatic diisocyanates as coupling agent. Here, we investigated whether different morphologies could be obtained for PDCs synthesized from identical oligomeric macrodiols (PCL-diol with M n = 2000 g·mol-1 and PPDO-diol with M n = 5300-5500 g·mol-1) with 2, 2(4), 4-trimethyl-hexamethylene diisocyanate (TMDI) and 1, 6-hexamethylene diisocyanate (HDI), respectively. More specifically, atomic force microscopy (AFM) was utilized for an investigation of the surface morphologies in solution casted PDC thin films in the temperature range from 20 °C to 60 °C. The results obtained in differential scanning calorimetry (DSC) and AFM demonstrated that different morphologies were obtained when TMDI (PDC-TMDI) or HDI (PDC-HDI) were used as linker. PCL related crystals in PDC-HDI were more heterogeneous and less ordered than those in PDCTMDI, while HDI resulted in a larger degree of crystallinity than TMDI. This research provides some new suggestions for choosing a suitable coupling agent to tailor the required morphologies and properties of SMPs with crystallizable switching segments.

We have developed a method of a stepwise construction of a gel consisting of (i) astral-shaped actin filaments with their plus end connected on photo-responsive polymer beads and (ii) bipolar myosin filaments as linkers in order to mimic sarcomeric structure, the basic unit of a muscle. In the method, firstly, 4 μm diam. beads were prepared from an acrylate polymer containing azobenzene moiety by a good-solvent evaporation technique. Next, gelsolin, which servers and remains bound to the plus end of an actin filament, was adsorbed and then immobilized on the bead surface by exposure to light from blue light-emitting diodes, and then fluorescent actin filaments were mixed with the beads. Formation of star-like, astral actin filaments on the beads were observed in fluorescent microscopy. Finally, the beads with actin filaments were mixed with myosin mini filaments with ca. 1 μm in length. Dozens of the beads were observed to be assembled into a gel form in optical microscopy. After adding adenosine triphosphate to the gel solution, the gel was slowly contract up to 60% comparing with its original volume, suggesting that linker myosin filaments moved on the actin filaments toward the plus end on the beads.

We report on the study of single devices of phase-change (Ge2Sb2Te5) memory cells in line cell type devices. Devices were investigated employing an x-ray nanobeam of only about 150 nm diameter, which could be fully contained within the spatial extent of the active area within a single device cell. XANES spectra showing the device in the amorphous and crystalline state have been successfully collected after switching the device in situ at the synchrotron. By monitoring the fluorescence response of the sample constituent materials at a constant photon energy (corresponding to the Ge K-edge absorption edge) as a function of x-ray beam position on the sample 2D maps have been produced.

This work clearly demonstrates that the X Ray Reflectometry technique (XRR), extensively used to assess the quality of microelectronic devices can be a useful tool to study the first stages of ion beam mixing. This technique allows measuring the evolution of the Si concentration profile in irradiated Cr/Si layers. From the analysis of the XRR profiles, it clearly appears that the Si profile cannot be described by a simple error function.

Multi-junction III-V solar cells are based on a triple-junction design that employs a 1eV bottom junction grown on the GaAs substrate with a GaAs middle junction and a lattice-matched InGaP top junction. There are two possible approaches implementing the triple-junction design. The first approach is to utilize lattice-matched dilute nitride materials such as InGaAsN(Sb) and the second approach is to utilize lattice-mismatched InGaAs employing a metamorphic buffer layer (MBL). Both approaches have a potential to achieve high performance triple-junction solar cells. A record efficiency of 43.5% was achieved from multi-junction solar cells using the first approach [1] and the solar cells using the second approach yielded an efficiency of 41.1% [2]. We studied carrier dynamics and defects in bulk 1eV InGaAsNSb materials and InGaAs layers with MBL grown by MOVPE for multi-junction solar cells.

Papers in the Appendix were published in electronic format as Volume 1534

We have studied the LME phenomenon for the Cu/Hg couple, from an experimental and a computational point of view. We compared the LME behavior of standard oxygen free high conductivity (OFHC) copper with Grain Boundary Engineered (GBE) copper (containing a high fraction of special Σ3 GBs). Experimentally, we find that special Σ3 GBs in copper are less prone than general GB to LME by liquid mercury. In parallel, we have investigated the difference in LME induced fracture between the symmetric Σ3(111)[110]70.5° tilt GB and the symmetric Σ5(210)[100]36.87° tilt GB by ab-initio calculations. The Hg segregation trend has been evaluated for these 2 GBs. Ab-initio tensile tests on the Σ3(111) GB with and without segregated Hg atoms have been performed. Finally solid/liquid interfaces have been modeled using ab-initio molecular dynamics (AIMD) in order to calculate solid-liquid surface energies (γSL). Using a Griffith approach, we have evaluated the energy difference γGB - 2 γSL. The LME mechanism in Cu/Hg is discussed.

The high resolution X ray diffraction (HR-XRD) diagrams have been studied in the GaAs /InxGa1-xAs /In0.15Ga0.85As/GaAs quantum wells with embedded InAs quantum dots (QDs) in dependence on the composition of the capping InxGa1-xAs layers. The parameter x in capping InxGa1-xAs layers varied from the range 0.10-0.25. These technological changes have been accompanied by the variation non-monotonously of InAs QD emission. Numerical simulation of HR-XRD results has shown that the level of elastic strains and the composition of quantum layers vary none monotonously in studied QD structures. Simultaneously it was revealed that the process of Ga/In inter diffusion at the InxGa1-xAs/InAs QD interface are characterized by the dependence non monotonous versus parameter x in capping InxGa1-xAs layers. The physical reasons of the mentioned optical and structural effects in studied structures have been discussed.

High temperature (>550°C) applications of silver based porous composites have been limited due to relatively low melting temperature (962°C) of Ag. Incorporation of oxide particles was demonstrated as an effective approach for stabilization of the porous Ag microstructures. This study aims developing an understanding based on the relationships between the properties of the incorporated YSZ (yttria-stabilized zirconia), the developed porous microstructures and the electrochemical response of their electrodes. Minimum degradation was observed with the composite microstructure based on comparable Ag and YSZ particle sizes. The results demonstrated that YSZ incorporation into Ag matrix can increase the stable application temperature to 800°C.

Metal films on polymer substrates are commonly used in flexible electronic devices and as gas barrier coatings. One way to evaluate the fracture and adhesion properties of such film systems is the fragmentation test. In the fragmentation test a film-substrate system is strained in tension under an optical microscope or inside a scanning electron microscope to observe the cracking and delamination events in situ. The technique works very well for brittle metal and ceramic films. However, when ductile films are strained they deform plastically before cracks and buckles appear. Therefore, a tensile straining device was developed to fit under an AFM for in situ observation of ductile metal films on polymer substrates. With the new in situ device the first occurrence of plastic deformation in the form of localized thinning of the film and channel cracks are visible. These features can only be detected through a height difference in the AFM images and not with optical or scanning electron micrographs. A comparison to brittle Cr films on polymer substrates was performed.

A facile and cost-effective fabrication approach of active strain sensor based on individual ZnO micro/nanowire was demonstrated. By connecting a ZnO micro/nanowire along polar growth direction with two Ag electrodes on flexible polystyrene (PS) substrate, the fabricated strain sensor was obtained as a typical M-S-M structure. The I-V characteristic of the device was highly sensitive to the strain caused by the obvious change of Schottky barrier height (SBH). Furthermore, both of the symmetric and asymmetric changes of the SBH at the source and drain were observed during device testing process. The respective contribution of piezoresistance effect and the piezoelectric effect to the change of SBHs were also systematically investigated.

Solar water splitting has shown promise as a source of environmentally friendly hydrogen fuel. Understanding the interactions between semiconductor surfaces and water is essential to improve conversion efficiencies of water splitting systems. TiO2 has been widely adopted as a reference material and rutile surfaces have been studied experimentally and theoretically. Scanning Tunneling Microscopy (STM) is commonly used to study surfaces, as it probes the atomic and electronic structure of the surface layer. A systematic and transferable method to simulate constant current STM images using local atomic basis set methods is reported. This consists of adding more diffuse p and d functions to the basis sets of surface O and Ti atoms, in order to describe the long range tails of the conduction and valence bands (and, thus, the vacuum above the surface). The rutile TiO2 (110) surface is considered as a case study.

Molecular transport as an ageing process in emulsions is revisited using microfluidic droplet production, manipulation and analysis. We show how microfluidic systems provide extremely quantitative insights into the phenomenon. We designed microfluidic systems to address the specificity of molecular transport in fluorinated oils and showed the role of the surfactant solubilised in the oil phase on the time scale of the exchange and rationalize the effect of water soluble additives on the exchange rate. Finally, we also demonstrate that the droplet packing influences the exchange rate through the number of first neighbours.

Nanocomposites of gold nanoparticles (AuNPs) embedded in polyaniline fibers have been fabricated using a one-pot synthesis approach and in-situ polymerization. By using a combination of inorganic acids (e.g. HCl) and camphorsulfonic acid, polyaniline nanostructured fibers of high aspect ratio with diameters of 150 ± 50 nm and several micrometers in length were obtained. These fibers afforded high electrical conductivity of 4.2 ± 0.5 S/cm. Encapsulation of the AuNPs in the polyaniline fibers afforded nanocomposites with high electrical conductivity and dielectric constant of 34.0 ± 0.5 S/cm and 65.3 ± 5 respectively. The morphology of these materials was analyzed using SEM and HRTEM and electronic properties were analyzed using UV-Vis spectroscopy.

A new nano-fabrication process, utilizing protein supramolecules, biomineralization, and nano-etching was proposed, which was named Bio Nano Process (BNP). The main processes of the BNP include the nanoparticle (NP) or nanowire (NW) synthesis utilizing bio-template (biomineralization) and nanostructure fabrication utilizing self-organization of protein supramolecules. Proteins are so designed to produce the final structures. The space where nano functional structures are fabricated is named an “Active Bio-field”. It was proven that the process has vast potential to be applied to a wide range of quantum effect base nano-devices and thin film devices.

Carbon nanotubes (CNTs) have been considered as a promising interconnect material to replace the solder bump used in the flip chip package because of their special electrical, mechanical and thermal properties, which may promote both the performance and reliability of the flip chip packaging. In this paper, electrophoretic deposition (EPD) of CNTs on substrates has been demonstrated for the interconnect application. EPD is a simple, low cost and high throughput process that is capable to produce densely packed film with good homogeneity at low temperature. By altering the electric fields and deposition time during the EPD process, the thickness of the CNTs film could be controlled. In this study, multi-walled carbon nanotubes (MWCNTs) were successfully coated on the various substrates using the EPD method. A highly uniform CNTs microstructure film with thickness over 5 µm was achieved. In addition, the selective depositions of CNTs on the pre-defined bond pads to form CNTs bumps were also accomplished. By employing typical flip-chip bonding technique, high density CNTs bumps were aligned to form a test chip/host substrate interconnects. The electrical conductivity of the CNTs interconnects was carried out using four-point probe measurement. Reliable electrical contacts with linear relationship in the current-voltage (I-V) characteristic suggesting ohmic behaviour were attained. The overall resistances extracted were also relatively low. These superior electrical properties have demonstrated that the CNTs bumps deposited using EPD method is a viable way to serve as an alternative to current metal solder interconnects material such as Sn-Pb alloys. Hence, it offers a promising interconnect application in the quest for device miniaturization in microelectronic industry.

In order to achieve high performance, the design of devices for large-area electronics needs to be optimized despite material or fabrication shortcomings. In numerous emerging technologies thin-film transistor (TFT) performance is hindered by contact effects. Here, we show that contact effects can be used constructively to create devices with performance characteristics unachievable by conventional transistor designs. Source-gated transistors (SGTs) are not designed with increasing transistor speed, mobility or sub-threshold slope in mind, but rather with improving certain aspects critical for real-world large area electronics such as stability, uniformity, power efficiency and gain. SGTs can achieve considerably lower saturation voltage and power dissipation compared to conventional devices driven at the same current; higher output impedance for over two orders of magnitude higher intrinsic gain; improved bias stress stability in amorphous materials; higher resilience to processing variations; current virtually independent of source-drain gap, source-gate overlap and semiconductor thickness variations. Applications such as amplifiers and drivers for sensors and actuators, low cost large area analog or digital circuits could greatly benefit from incorporating the SGT architecture.

Recently, the oxides have received attention and great interest due to their magnetic ordering above of the room temperature by doping a very low amount of transition metal ions, which are very promising for applications such as biosensing, hyperthermia, doped magnetic semiconductors with lower energy losses and rapid response at alternating-magnetic fields. In this work the magnetic interactions on Fe doped ZnO thin-films was studied. Raman spectroscopy allowed the monitoring of iron ions diffusion and demonstrated that symmetry modes are crucial for understanding of the magnetic ordering. X-ray diffraction (XRD) was used to determine the oxidation state of the iron ions and stress into ZnO lattice. MFM confirmed that magnetic moments and magnetic forces on scanned surface depend on magnetic-domain structure formation.

CrB2 possess the hexagonal AlB2 structure which belongs to the spacegroup of P6/mmm. The compound exhibits para- to antiferro-magnetic transition at about 88 K. By using a macroscopic measurement technique, that is, a conventional resonant ultrasound spectroscopy (RUS) with a millimeter size mono-crystal, significant elastic anomalies have been observed just above the magnetic transition temperature. On the other hand, elastic constants determined by a microscopic measurement technique, that is, an inelastic X-ray scattering method (BL35XU of SPring-8, Japan) do not show any elastic anomalies at around the transition temperature. In order to explain the discrepancy, we have introduced a kind of so called ΔE effect resulting from a multidomain structure. If crystal lattice is slightly deformed by a spontaneous magnetostriction in the antiferromagnetic state, the symmetry of crystal lattice is lowered from hexagonal to monoclinic when the symmetry of magnetic structure is taken into account. By the lowering of the symmetry, the crystal consists of six magnetic domains in the antiferro magnetic state. If magnetic domain boundaries move in response to externally applied stresses, the mechanical deformation is absorbed by nonelastic deformations induced by the movement of magnetic domain boundaries. This multidomain model well explains the experimental results obtained by both microscopic (X-ray) and macroscopic (ultrasound) measurements. The microscopic measurement technique is useful to obtain the true elastic properties of crystal lattice without effects coming from a multidomain structure.