This paper presents the formation and the characterization of silicon germanium oxide (SixGeyO1-x-y) infrared sensitive material for uncooled microbolometers. RF magnetron sputtering was used to simultaneously deposit Si and Ge thin films in an Ar/O2 environment at room temperature. The effects of varying Si and O composition on the thin film's electrical properties which include temperature coefficient of resistance (TCR) and resistivity were investigated. The highest achieved TCR and the corresponding resistivity at room temperature were -5.41 %/K and 3.16×103 ohm cm using Si0.039Ge0.875O0.086 for films deposited at room temperature.

This study describes the covering process of dental burs with CVD diamond and the quality of its cut during dental procedure proving, at the same time, its advantages in comparison to regular dental burs. Ten equals burs made of tungsten carbide (WC) were covered with CVD diamond trough Hot Filament Chemical Vapor Deposition technique (HFCVD), varying thickness and temperature of deposit, leaving constant the rest of the deposit parameters like pressure (50 mbar) and gas flow (H2 and CH4). Dental cuts were comparing in a standard cutting device. The burs as well as the cuts were analyzed trough Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Analysis (EDX), what allow obtaining accurate measures of cuts and covering is chemical components. The quality and stress of the grown diamond was characterized by Raman analysis.

The crystallinity of the hydrogenated microcrystalline silicon (μc-Si:H) film was known to influence the solar cell efficiency greatly. Also hydrogen was found to play a critical role in controlling the crystallinity. Instead of employing conventional plasma deposition techniques, this work focused on using catalytic chemical vapor deposition (Cat-CVD) to study the effect of hydrogen dilution and the filament-to-substrate distance on the crystallinity, deposition rate, microstructure factor and electrical property of the μc-Si:H film. We found that the substrate material and structure can affect the crystallinity of the μc-Si:H film and the incubation effect. Comparing bare glass, TCO-coated glass, a-Si:H-coated glass and μc-Si:H-coated glass, the microcrystalline phase grows the fastest onto μc-Si:H surface, but the slowest onto a-Si:H surface. Surprisingly, the template effect lasted for more than a thousand atomic layers of silicon.

In 3D packaging, Through Silicon Vias (TSVs) with high aspect ratios and depths measuring tens of microns are filled by advanced Cu electroplating processes. Today's 300mm TSV plating platforms are intended to produce bottom-up via fill, no seam voids, and minimal, controlled overburden. To achieve this, the preceding Cu-seed coverage must be continuous at a constant resistance, and the plating chemistries optimized. However, other factors such as hardware configurations and simple depletion of the plating formulations during the extended TSV process can lead to high Cu overburden thickness requiring a high removal rate (HRR) chemical-mechanical polish (CMP) process to remove the thick Cu layer.

Presented here are CMP results of a thick Cu overburden (~6um) resulting from the fill of 5 x 25um TSVs on 300mm wafers. The goal is to uniformly polish the overburden and utilize the tool's endpoint system at Cu clear before the next step of conventional barrier CMP. Slurries were screened for removal rate, uniformity, planarization ability, and defectivity. This study focuses on achieving a removal rate of >2.5um/min through evaluation of several commercial slurries in a multi-step polish application. Cross-sections post-plating show the Cu overburden, barrier and liner layer. Cross-sections post-CMP quantify Cu recess, dielectric loss, and presence/absence of seam defects. The process selected is demonstrated to achieve good planarization results with low occurrence of polish defects, at a rate and selectivity suitable for emerging 3D TSV Cu CMP applications.

Silicon carbide (SiC) semiconductor devices for high power are becoming more mature and are now commercially available as discrete devices. Schottky diodes have been on the market since a few years but also bipolar junction transistors (BJTs), JFETs and MOSFETs are now reaching the market. The interest is rapidly growing for these devices in high power and high temperature applications. The BJTs have low conduction losses, fast switching capability, operate in normally-off mode, have high radiation hardness, and can handle high power density.

This paper will review the current state of the art in active switching device performance with special emphasis on BJTs. Device performance has been demonstrated over a wide temperature interval. A very important feature in high power switch applications is the low on-resistance of a device. Better material quality and epi processes suppress the amount of basal plane dislocations to avoid stacking fault formation generated during high current injection. This has long been a concern for bipolar SiC devices but several research reports and long term reliability measurements of pn-junctions show that the bipolar degradation problem can be solved by a fine-tuned epitaxial technique. A discussion on surface passivation control is included.

Finally, an example of a power switching module is given also demonstrating the excellent paralleling capability of BJTs.

Graphene has been grown by direct deposition of carbon from solid sources on both SiC and Ta films on SiC in an MBE environment. Carbon fluxes were obtained from thermally evaporated C60 and from a heated graphite filament. The graphene films were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy. Graphene films on Si-face SiC grown by carbon source MBE (CSMBE) were compared with graphene grown by the standard epitaxial graphene process using SiC thermal decomposition. CSMBE on SiC was found to grow at lower temperatures (1200°C) and to have fewer pits and a more uniform surface. Uniform graphene films were found to grow on Ta films after exposure to both carbon sources at 1200°C but Raman measurements showed no signs of graphene on films exposed to the same temperature without a carbon flux.

TiO2nanoparticles were synthesized by the Sol-Gel method by using 2-propanol as solvent in acid medium (pH1). The samples were annealed at 200 and 500°C and were characterized by BET, XRD-Rietveld refinements, TEM and FTIR. The activity was evaluated by the acetaldehyde photodecomposition in an isolated chamber with an initial concentration of contaminant of 300 ppmv with oxygen (2%) assisted with a 365-nm UV lamp. The test results were compared with those obtained with a commercial catalyst (P25). Improved photoactivity (≍100 % of acetaldehyde in 150 min) was obtained with catalysts annealed at 200°C (TiO2-P-200°C), that showed nanoparticles (≍7 nm) and abundant anatase phase (≍ 63 %) coexist with the brookite phase (≍ 37 %), as well as irregular equiaxial morphology. The samples annealed at 500°C (TiO2-P-500°C), showed an increment in nanoparticles (≍22 nm), different ratio and phase composition (anatase-brookite-rutile), and therefore less activity (≍80 %). This high activity could be explained by the special ratio of anatase-brookite and the dimension of nanometric crystal size. The aforementioned characteristics could be useful in the degradation of reactive organic gases like acetaldehyde either in confined spaces or in the open air.

This work aims at attaining a more complete understanding of the principles governing resistive contrast imaging (RCI) of copper/low-k interconnects used for dielectric breakdown studies in a nanoprober scanning electron microscope (SEM) system. RCI is employed in such in situ dielectric breakdown studies to facilitate the localization of interconnect defect sites related to various stages in the degradation process of the low-k dielectric material. This work shows that RCI is suitable for detecting high-resistance sites, like opens, in copper/low-k interconnects. Moreover, RCI demonstrates potential in locating defects that lie deep in the test structure and are, thus, not detectable by SEM. A model is also proposed to explain the formation of RCI images of specific interconnect test structures with complex layout.

Through-silicon via (TSV) structures with various material and geometry configurations are assessed to study their impact on reliability, isolation and performance. Oxide liner insulators show a larger performance impact as compared to low-k liners and the effect decreases with increasing liner insulator thickness. Higher density of the TSV array causes greater stress impact on carrier mobility and increases the parasitic capacitance. Additionally, low-k liner reduces the parasitic capacitance, but exhibits lower strength and adhesion, therefore degraded reliability. These results provide an important perspective of performance and reliability trade-offs necessary for a robust TSV design.

This investigation examines the used parameters in the wet welding process, as well as his influence on the properties of welded union under manual metal arc welding process, obtained at 10m and 20m sea water deep, with an electrode E7024. The E7024 filler material is normally used in the reparation of hydrocarbon pipelines on deeps no more of 30m, however his chemical composition allow to use as material to repair in zones where the pressure is a paramount factor. A statistical design of experiments (DOE) with 36 coupons has been proposed using the travel speed, amperage and the underwater welding condition (10m and 20m) as input variables. To evaluate the quality of the welded unions, tensile, bend, hardness and metallographic test were carried out. The statistical analysis of DOE found that the amperage variable result to be the most influence parameter in the control of quality of the weld union. Besides this the technique of scanning electron microscopic was used to observe the kind of fractography showed in a crack throughout weld resulted from the bend test, and energy dispersive X-ray spectrometry to identify the present species in this zone.

The present work is devoted to study the development of yttria-stabilized zirconia membranes self-supported on silicon-based microplatforms, to be used as electrolytes on micro solid oxide fuel cells. The microfabrication process to obtain yttria-stabilized zirconia membranes is detailed, and some key aspects for the integration of yttria-stabilized zirconia films deposited by pulsed laser deposition on the silicon-based microplatform are shown. Moreover, the effect on the thermomechanical stability of different fabrication parameters is presented, as well as the way to control the pinhole generation on the membranes. Finally, some electrical characterization guidelines are included, in order to study the effects of the platform and the membrane dimensions on the different measurements performed.

The thermoelectric (Pb1-mSnmTe)1-x(PbS)x where m = 0.05 and x = 0.08 has been shown to produce PbS nanostructures that effectively scatter phonons, enhancing ZT. As Sn substitution is increased, a new phase of PbSnS2 precipitates. We find that incorporation of PbSnS2 in PbTe results in a significant reduction in lattice thermal conductivity around 0.6 W/mK at room temperature. We present preliminary characterization and thermoelectric properties.

A novel, flexible and ductile organic field-effect transistor (OFET) able to detect pH changes in chemical solutions has been realized and successfully tested. With respect to other organic pH sensors, based on an ISFET-like structure, in our approach the organic transistor is completely separated from the sensing active area and its gate is left floating. The device is biased with a fourth electrode (control-gate) capacitively coupled to the floating-gate. The floating-gate is functionalized by deposition of a layer of thio-amines able to protonize proportionally to the pH value of the solution thus modulating the drain current. The structure does not need an Ag/AgCl counter-electrode since the control-gate is not in contact with the solution. Moreover, the sensing mechanism does not depend on the choice of the dielectric and semiconductor material since the working principle is based on charge separation in the metal induced by the electric field. This structure also simplifies the realization of the fluidics since all the contactable electrodes (drain, source and control-gate) are on the same side of the substrate. A differential measurement approach was adopted in order to get rid of device aging and process-related fluctuations. With the same structure, other chemical species may be detected provided that a proper functionalization procedure is adopted.

Sputter deposited YSZ thin films were studied for the application as electrolyte membrane in micro solid oxide fuel cells. A new micro-machined test structure was developed to test 200 μm fuel cell membranes that are integrated onto silicon substrates. The membranes are liberated by means of deep silicon dry etching from the backside, and both contacts are situated on the front side of the wafer. Annular Pt electrodes provide contacts to specific anode and cathode layers. Preliminary tests are reported for the situation without specific electrodes. At 450 °C, an OCV of 570 mV, and a maximal power of about 0.55 mW/cm2 is obtained. LaSrMnO electrodes deposited by pulsed laser deposition were evaluated by electrical impedance spectroscopy. The dense films yielded too high ASR values. Interestingly, these could be reduced by applying a DC bias voltage.

The effect of different combinations of a new tri-templating agent TEAOH/DEA/TEA, namely tetraethyl ammonium hydroxide (TEAOH)/diethylamine (DEA)/triethylamine (TEA), on the catalytic performance of SAPO-34 was investigated in MTO conversion. It was found that SAPO-34 and SAPO-5 are competing phases at TEA concentrations higher than 40 %. Pure SAPO-34 with high crystallinity, large BET surface area and small crystal size (0.8~1.4μm) was obtained at a low TEA concentrations. The combination of TEAOH/DEA/TEA strongly governed the acidity of crystals. TEAOH:DEA:TEA=0.67:0.67:0.67 gave an economical catalyst active in MTO reaction with 100 % methanol conversion, 89.39 % ethylene and propylene selectivity, a longest lifetime and a high coke capability of 24.2 wt %.

A simple and efficient approach for fabricating silicon nanopillar arrays with a high aspect ratio and controllable sidewall profiles has been developed by using holographic lithography and a novel single-step deep reactive ion etching. During the etching process, scalloping of the sidewalls can be avoided while reserving the high mask selectivity and high etching rate. Besides, the sidewall angle of resultant patterns can be adjusted by tuning the composition of the gas mixture of single-step DRIE process. We further fabricate a tapered silicon nanopillar array and observe its photonic bandgap property. We believe that the good optical performance of this tapered silicon nanopillar array realized by the proposed approach shows the promising of this process for various applications.

Lithium borophosphate glasses 0.45Li2O-(0.55-x)P2O5-xB2O3 (where 0 ≤ x ≤ 0.40) were investigated focusing on the influence of cation mobility changes due to mixed glass former effect. It was found that glass transition temperature (Tg) increases and molar volume decreases with B2O3 addition. X-ray photoelectron spectroscopy (XPS) spectra showed that besides P-O-P, B-O-B and P=O, P-O-, B-O- bond peaks, an intermediate O1s peak due to P-O-B bonds emerges in glasses with B2O3 contents x ≥ 0.15. Molecular dynamics (MD) simulations for the same systems have been performed with an optimized potential, fitted to match bond lengths, coordination numbers and ionic conductivity (σdc). Structural effects on ion transport as the origin of the mixed glass former effect can be quantified by applying the bond valence analysis (BV) approach to the equilibrated MD trajectories.

Optical, electrical and structural properties of silicon films depending on hydrogen flow rate (RH ), substrate temperature (TS ), and deposition pressure (PD ) were investigated. By decreasing RH and increasing TS and PD , the optical band gap (Eopt ) of silicon thin films drastically declined from 1.8 to 1.63 eV without a big deterioration in electrical properties. We employed all the investigated Si thin films for p-i-n structured solar cells as absorbers with i-layer thickness of 300 nm. From the measurement of solar cell performances, it was clearly observed that spectral response in long wavelength was enhanced as Eopt of absorber layers decreased. Using the solar cell whose Eopt of i-layer was 1.65 eV, the highest QE at long wavelength with the short circuit current density (Jsc ) of 16.34 mA/cm2 was achieved, and open circuit voltage (Voc ), fill factor (FF), and conversion efficiency (η) were 0.66 V, 0.57, and 6.13%, respectively.

Variable frequency microwaves (VFM) and rapid thermal annealing (RTA) were used to activate ion implanted dopants and re-grow implant-damaged silicon. Four-point-probe measurements were used to determine the extent of dopant activation and revealed comparable resistivities for 30 seconds of RTA annealing at 900 °C and 6-9 minutes of VFM annealing at 540 °C. Ion channeling analysis spectra revealed that microwave heating removes the Si damage that results from arsenic ion implantation to an extent comparable to RTA. Cross-section transmission electron microscopy demonstrates that the silicon lattice regains nearly all of its crystallinity after microwave processing of arsenic implanted silicon. Secondary ion mass spectroscopy reveals limited diffusion of dopants in VFM processed samples when compared to rapid thermal annealing. Our results establish that VFM is an effective means of low-temperature dopant activation in ion-implanted Si.

Ni-NiO 30% electrodes coated with LiMg0.05Co0.95O2 cobaltite deposited on the substrate by complex sol-gel process were investigated by neutron diffraction. The measurements were carried out at the D20 diffractometer at the High Flux Reactor of the Institut Max von Laue – Paul Langevin. As the catalytic layer is only a few microns thick, the diffracting volume of the cobaltite phase was optimised by stacking small rectangular pieces cut from the original electrode and assuming that the catalytic layer on the electrodes was homogenous. A pure cobaltite sample was used as a reference for identifying in the complete electrode the diffraction peaks of the catalytic layer. Both an as-received sample and an electrode tested for 100 h at 650 °C in a cell were measured. Despite the small diffracting volume, due to the high flux available at D20, it was possible to detect the hexagonal phase of the catalytic layer and estimate its volume fraction in the as-received sample; in the tested electrode the original crystallographic structure is completely modified but information on the phases present can be obtained.