The current trend in magnetoresistive sensors development is to increase the sensitivity of single sensing elements by using multilayer structures and to design them into arrays. Such arrays are designed to compensate the excess low frequency noise of individual elements, which limits their magnetic resolution. Here, we report the modeling, design, and fabrication of single layer anisotropic magnetoresistive (AMR) sensors using low noise epitaxial La2/3Sr1/3MnO3 (LSMO) oxide thin films deposited on vicinal SrTiO3 substrates. The fabrication process is simple, and the operation of the sensor is based on a step-induced uniaxial magnetic anisotropy, described using the Stoner-Wohlfarth model. A coherent magnetization reversal process is observed by magneto-optical Kerr effect imaging. A good agreement between experimental data and the expected sensor response confirms the correct operation of the device. Three main fabrication parameters, namely the vicinal angle of the substrate, the deposition temperature, the thin film thickness, and their effects on film anisotropy field and device detectivity have been studied. Detectivity levels as low as 1.4 nT Hz-1/2 at 1 Hz and 240 pT Hz-1/2 in the white noise region are achieved with a single Wheatstone bridge element operating at 310 K. Compared to GMR and AMR sensors, these results are promising for further development and for their use as single layer LSMO low field AMR sensors, including applications as implantable biomedical devices.

Macrostructure, microstructure, and distribution of phases through the interface were analyzed for friction-stir-welded joints 5083 aluminum alloy and 316L steel. Several analytical techniques, including light microscopy, transmission and scanning electron microscopy, elemental analysis using X-ray spectroscopy, and electron diffraction, were used to thoroughly analyze the weld interface. The interface is characterized by a significant reduction in grain size for both aluminum alloy and stainless steel. New compounds, not corresponding to thermodynamically stable phases in the binary Al–Fe phase diagram, were found in the stirred zone (SZ) as dispersed particles. On the steel side of the welding, thin slabs of new compounds were found, as well, being interlaced with the stainless steel. The observations support that the grain refinement of stainless steel is likely due to a continuous dynamic recrystallization. The intermetallic compounds present as a layer at the interface, exhibiting nanometric grain size, were identified by electron diffraction as Al 13 Fe 4 and Al 5 Fe 2 phases. Concerning the intermetallic compound formed in SZ, the elemental analysis showed a compound containing principally Al and Fe, with admixture of Si and Mn. It was concluded that it is a pseudo-ternary compound with body-centered cubic structure, Im -3 space group, which is for the first time reported in this kind of dissimilar assembly, and is known as α-Al(Fe,Mn)Si.

We report the integration of high-quality epitaxial La2/3Sr1/3MnO3 (LSMO) thin films onto SrTiO3 buffered Silicon-on-Sapphire (SOS) substrates by combining state-of-the-art thin film growth techniques such as molecular beam epitaxy and pulsed laser deposition. Detailed structural, magnetic and electrical characterizations of the LSMO/STO/SOS heterostructures show that the LSMO film properties are competitive with those directly grown on oxide substrates. X-ray magnetic circular dichroism measurements on Mn L2,3 edges show strong dichroic signal at room temperature, and angular-dependent in-plane magnetic properties by magneto-optical Kerr magnetometry reveal isotropic magnetic anisotropy. Suspended micro-bridges were thus finally fabricated by silicon micromachining, thus demonstrating the potential use of integrating LSMO magnetic layer on industrially compatible SOS substrates for the development of applicative MEMS devices.

Though manufacturing spheroidal graphite cast irons is a well-established industrial process, good nodularity which is essential for mechanical properties may be hampered by several factors. Amongst them is the presence of impurities at trace level which lead to the growth of protrusions and the question is how they can destroy the spheroidizing effect of magnesium. For the first time, it is shown that such impurities are present together with magnesium at the interface between spheroid and protrusion. For getting this result, site-specific electron transparent lamellae were prepared using Focused Ion Beam and characterized at nanometric scale using atomic resolution scanning-transmission electron microscope. It is also shown by automatic crystal orientation mapping that there is no definite crystallographic relationship between protrusions and underlying spheroids.

Lead zirconate titanate Pb(Zr,Ti)O 3 (PZT) is a well know ferroelectric material with excellent piezoelectric properties, namely large piezoelectric coefficients, low leakage current and reliable performance, which makes it very suitable as an actuator material in Micro-ElectroMechanical Systems (MEMS). The performance of piezoelectric MEMS is, however, strongly dependent on the film quality. In the present work, the epitaxial growth of PZT is desired as it can help to reduce high-frequency losses, to allow for larger electromechanical coupling and to increase the final device sensitivity. We used an epitaxially grown conductive oxide bottom electrode, namely 45 nm thick La 2/3 Sr 1/3 MnO 3 (LSMO) films, deposited on SrTiO 3 buffered (001) silicon substrates using a combination of pulsed laser deposition and reactive molecular beam epitaxy techniques. The 500 nm thick c-axis oriented PZT layers were deposited at 600°C by magnetron sputtering on the LSMO films on STO/Si (001). The piezoelectric and ferroelectric properties of the PZT layers were studied by PiezoForce Microscopy on as-grown PZT films and Polarization versus Electric field measurements on samples covered with Pt top electrodes. The PZT films exhibited good piezoelectric and ferroelectric properties with a remanent polarization higher than 20 µC·cm −2 , which makes them suitable for the fabrication of piezoelectric MEMS based on doubly-clamped LSMO suspended structures.

In this work, the grain boundaries composition of the polycrystalline CaCu3Ti4O12 (CCTO) was investigated. A Focused Ion Beam (FIB)/lift-out technique was used to prepare site-specific thin samples of the grain boundaries interface of CCTO ceramics. Scanning transmission electron microscopy (STEM) coupled with energy dispersive X-ray spectrometry (EDXS) and Electron Energy Loss Spectroscopy (EELS) systems were used to characterize the composition and nanostructure of the grain and grain boundaries region. It is known that during conventional sintering, discontinuous grain growth occurs and a Cu-rich phase appears at grain boundaries. This Cu-rich phase may affect the final dielectric properties of CCTO but its structure and chemical composition remained unknown. For the first time, this high-resolution FIB-TEM-STEM study of CCTO interfacial region highlights the composition of the phases segregated at grain boundaries namely CuO, Cu2O and the metastable phase Cu3TiO4.

Short-circuit diffusion in fine-grained Ni samples processed by Spark Plasma sintering has been investigated by the radiotracer technique. Ni grain boundary self-diffusion is measured in samples sintered from commercial as-received powder and from a powder processed by mechanical milling (MM). Both samples displayed high penetration of the radiotracer and ultrafast diffusion rates, which exceed the diffusivity along general high-angle grain boundaries as they are present in pure polycrystalline Ni. A distinct profile was observed for each sample, dependent on the precursor powder. A stable penetration profile after pre-annealing at 773 K was observed when using commercial powder whereas a decrease in the grain boundary diffusion coefficient was depicted for the sample prepared from MM powders. The latter observation was interpreted in terms of partial relaxation of non-equilibrium grain boundaries generated by MM. Sample preparation by focused ion beam enabled the observation of interconnected porous paths in the sample prepared from commercial powders, which represent the main ultrafast diffusion path. A measurement of the surface diffusion coefficient through the pores was attempted considering a B–C-type kinetic regime. The isolated pores observed in the sample prepared from MM powder suggest a complex hierarchy of diffusion paths.

The microstructure of heavy section nodular graphite cast irons often presents a bimodal distribution of nodule size associated with so-called primary and secondary graphite nucleation. It has been found that the nuclei in both types of nodules consist mainly in magnesium sulphide. However, nuclei in primary nodules contain some traces of calcium and are thus related with the inoculation treatment. On the contrary, nuclei in secondary nodules do not contain any element that could be associated to inoculation. It is suggested they form in the late stage of the eutectic reaction as a result of microsegregation build-up in magnesium and sulphur.

TbxDy1 − xFe2 (Terfenol-D) thin films were grown in situ at 500 °C on Pt/TiO2/SiO2/Si substrate by multi-target sputtering. The thickness effect of the Terfenol-D layer on the microstructure and on the magnetic properties was investigated. Magnetic force microscopy was used to observe local domain patterns. Strong changes in the shape of magnetic domains were observed when the thickness of the Terfenol-D film was increased. Transmission Electron Microscopy observations showed that in situ elaboration at 500 °C gives rise to large diffusion of the platinum of the bottom electrode into the Terfenol-D film leading to different sub-layers. Saturation magnetization values increased from 500 to 840 kA/m, and coercive fields from 15 to 140 kA/m, respectively, when the thickness of the Terfenol-D film was varied from 100 to 1000 nm. Co-sputtering of Pt and Terfenol-D through the entire film thickness led to a similar saturation magnetization as well as an interesting strong decrease of the coercive field of these mixed films.

The cationic and anionic disorder in the Cu2ZnSnSe4-Cu2ZnSnS4 (CZTSe-CZTS) system has been investigated through a chemical crystallography approach including X-ray diffraction (in conventional and resonant setup), 119Sn and 77Se NMR spectroscopy, and high-resolution transmission electron microscopy (HRTEM) techniques. Single-crystal XRD analysis demonstrates that the studied compounds behave as a solid solution with the kesterite crystal structure in the whole S/(S + Se) composition range. As previously reported for pure sulfide and pure selenide compounds, the 119Sn NMR spectroscopy study gives clear evidence that the level of Cu/Zn disorder in mixed S/Se compounds depends on the thermal history of the samples (slow cooled or quenched). This conclusion is also supported by the investigation of the 77Se NMR spectra. The resonant single-crystal XRD technique shows that regardless of the duration of annealing step below the order-disorder critical temperature the ordering is not a long-range phenomenon. Finally, for the very first time, HREM images of pure selenide and mixed S/Se crystals clearly show that these compounds have different microstructures. Indeed, only the mixed S/Se compound exhibits a mosaic-type contrast which could be the sign of short-range anionic order. Calculated images corroborate that HRTEM contrast is highly dependent on the nature of the anion as well as on the local anionic order.

Anisotropic Liquid Crystal Polymer (LCP) substrates are used to design 3D conformal antenna elements and filtering structures in Laser Direct Structuring technology (LDS) for applications including 5G connected objects and massive Internet of Things (IoT): e.g., wearable (smart watches/rings), mobile (smartphones/tablets), home (appliances/lighting) devices. Based on the experimentally extracted optical absorption and refraction properties, identification of chemical and/or morphologic composition of the characterized samples (solid and liquid materials) are targeted. Perspectives for macro-modeling of composite materials and nano-Particles using homogeneization techniques are drawn.

In this paper, modeling and experimental characterization of bond-wire arrays are proposed based on dedicated pilote carriers designed and fabricated for RF and microwave applications. Effects of the number of wire elements, connected in parallel to build bond-wire arrays, on the values of extracted broadband parasitics are investigated. Physical characterization of molding compound materials is proposed for their structural analysis and for broadband extraction of their dielctric properties (complex permittivity). Influence of molding compound properties on extracted parasitics of bond-wire arrays is highlighted.

The development of the use of flax fibre as reinforcement of eco-friendly composite materials requires a good knowledge of its hydrothermal and mechanical behaviours. To this end the fibre internal structure must be finely investigated. Transmission electron microscopy was used to analyse the morphology of the fibre cell walls in terms of the arrangement of the layers and their thickness. Thus, an alternative eco-friendly staining method, based on oolong tea extract was successfully implemented. The results reveal an arrangement at the nanoscale slightly different from the classical four layer model encountered in the literature: the inner layer includes three to four sub-layers. The cell walls comprises two outer layers of relative thickness of about 10 %, a middle layer of about 70 % and a group of thinner layers (called sub-layers) that are contiguous to the lumen with relative thickness of about 20 %.

With electronics technology improvements, Electrical OverStress (EOS) failures due to Over Voltage Stress (OVS) event became the current issue instead of ElectroStatic Discharge (ESD). To better specify devices Absolute Maximum Rating (AMR), this study deepens the knowledge of robustness threshold and helps understanding failure mechanisms on ICs components besides ESD.

Study of the solid-state diffusion between copper and aluminum was carried out in the temperature range [573–673] K in order to better understand the aging mechanisms which occur in copper-clad aluminum thin wires. A complete microscopic analysis was performed to evaluate the interface composition and corresponding microstructure. The intermetallic phases developed during annealing identified by TEM and X-Ray diffraction analysis are respectively Al2Cu, AlCu, and Al4Cu9. A fine layer containing nanometric copper grains was also depicted and identified as a diffusion-induced recrystallization region. These results agree with EDXS analysis and nanoindentation measurements. The effective heat of formation model was used to evaluate the first phase(s) which happens in the interface and the sequence formation of intermetallic compounds during annealing. This model finely describes the metallurgical aging of copper-clad aluminum wires and explains the presence of only three intermetallic compounds in the interface between copper and aluminum.

Creep tests were performed on copper-clad aluminum wires at 423 K and different stresses to cover potential operating load ranges in automotive industry. The lifetime of the wires is strongly dependent on the existence of an initial heat treatment and on the applied stress. It can be correlated with the formation of the three intermetallics Al2Cu, AlCu and Al4Cu9 identified by TEM diffraction. All results are discussed to understand mechanisms that could lead to the embrittlement of copper-clad aluminum wires by creep.

In order to reduce costs and improve the bonding process, silver has been recently introduced as an alternative to common bonding wire metals (gold, aluminum, copper), leading to new failure analysis issues. This study compares the efficiency of wet and dry chemistries for decapsulation on three Ag-based alloy wires.

TbxDy1-xFe2 thin films are grown on Pt/TiO2/SiO2/Si substrate by multi-target sputtering. In order to achieve the best magnetic properties, samples grown while heating the sample holder (in situ films) are compared to those prepared at room temperature followed by thermal annealing. The effect of Tb, Dy and Fe content is also examined. It is found that the magnetic properties are very sensitive to the deposition parameters. Magnetization value as high as 680 emu/cm(3) with very low coercivity is achieved in a 140 nm thick film whose composition (Tb0.3Dy0.7)Fe-2 corresponds to the TERFENOL-D formulation. Observation of soft ferromagnetism and high magnetization are related to crystallization of nano-grains (size 7-10 nm) as deduced from microstructure investigation by X ray diffraction and transmission electron microscopy. It is shown the possibility of growing TERFENOL-D thin films with properties suitable for observation of extrinsic magneto-electric coupling in future thin film devices combining piezoelectric and magnetostrictive materials on metallized silicon substrate. (C) 2013 Elsevier B.V. All rights reserved.

In this paper, we present a study of conduction mechanisms observed in high performance SIS capacitors (semiconductor–insulator–semiconductor) fabricated on bulk silicon. The combination of high aspect ratio 3D patterns and thin dielectric layers enables amazing capacitance density values. Electrical measurement and modeling of leakage currents have been associated with structural analysis in order to characterize different oxide–nitride stacks, and thus, to scale the layers and reach even higher capacitance densities. Conduction mechanisms are relevant of Fowler–Nordheim tunneling and Poole–Frenkel emission.

Some process abnormalities can be very difficult to detect with conventional FA techniques. Scanning Capacitance Microscopy (SCM) has been shown to be a reliable and versatile tool and the case analysis presented in this work illustrates its significant role. In this paper, a 3D-PICS capacitor used as an element of a band pass filter of a cardiac detection chain was studied. As the electrical and physical diode current signature of this device did not satisfy the targeted needs, a complete failure analysis flow was performed, including OBIRCH and Scanning Capacitance Microscopy characterizations. SCM accumulated measurements allowed extracting and validating a trend according to electrical performance variations from the center to the edge of the wafer. As a result, the root cause of the level of this diode reverse current was identified and corrective actions could be introduced in the process to meet the application requirements.