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Although silicide oxidation was studied 20 years ago, the interest of obtaining a robust process for new application appears significant today. Indeed, for the new architectural development process are required dense and narrow spaces. This paper focuses to bury a silicide layer under a protective layer such as silica in order to keep constant the physical and electrical properties of silicide after oxidation. Earlier works show the possibility to oxidize preferably the silicon (Si) in metal contained silicide rather than a pure crystalline Si at high temperatures. Thus, we first tried to reproduce and study these conditions and once acquired, targeted to decrease the oxidation temperature in order to fit with industrial requirements. Titanium (Ti) and Nickel (Ni) are chosen for their metallurgical interest and their integration capability in devices. Thus, four different group/phases (TiSi, TiSi 2 , Ni 2 Si, NiSi) of silicide were targeted by adjusting the temperature. In situ X-ray diffraction (XRD), photoelectron spectroscopy and sheet resistance (four point probe) measurements were carried out simultaneously before and after oxidation of silicide to characterize the phase and chemical composition. After silicide formation last three phases (TiSi 2 , Ni 2 Si, NiSi) were confirmed by XRD and G1(Ti/Si) was unknown, where only for NiSi was observed the low sheet resistance (≈7.3 Ω/□) and resistivity (18 μΩ·cm). After (dry, wet and plasma) oxidation, the phases of TiSi 2 and Ni 2 Si changed and only NiSi was observed the constant phase, even pure SiO 2 was noted on NiSi after wet oxidation. [ABSTRACT FROM AUTHOR]

The fast-growing market of GaN-based power electronics requires the development of performing ohmic contacts. The Ti/Al stack, being one of the most popular, has been thoughtfully investigated over the years in terms of electrical performances but remains to be better understood in terms of contact formation and related solid-state reactions, especially when targeting small Ti to Al ratios (typically, down to lower than 5 at. %). In this paper, the influence of the deposited Ti layer thickness on the resulting contact is investigated using in-situ and ex-situ XRD methods as well as TEM imaging. It is found that a threshold exists, below which the diffusion phenomena ruling alloy formation during annealing are controlled, leading to a frozen Al 3 Ti/Al bi-layer morphology. Past this threshold, the erratic formation of non-textured Al 3 Ti grains is observed, which is detrimental to devices performances. The result interpretation is supported by an extended bibliography survey focused on material science, the first of the sort. [ABSTRACT FROM AUTHOR]

We present a study of the chemistry of the nanostructured phase at the surface of lead zirconium titanate PbZr 0.52 Ti 0.48 O 3 (PZT) films synthesized by sol–gel method. In sol–gel synthesis, excess lead precursor is used to maintain the target stoichiometry. Surface nanostructures appear at 10% excess whereas 30% excess inhibits their formation. Using the surface-sensitive, quantitative X-ray photoelectron spectroscopy and glancing angle X-ray diffraction we have shown that the chemical composition of the nanostructures is ZrO 1.82−1.89 rather than pyrochlore often described in the literature. The presence of a possibly discontinuous layer of wide band gap ZrO 1.82−1.89 could be of importance in determining the electrical properties of PZT-based metal-insulator-metal heterostructures. [ABSTRACT FROM AUTHOR]

Abstract: An analytical model is presented in order to derive a general expression for the flow stress in polycrystalline films which encompasses and correlates dimensional constraints and strengthening effects. The model is based on the Thompson approach, which is extended to take into account both different grain aspect ratios and distinct strengthening contributions. It allows an accurate prediction of the growth textures in polycrystalline CdTe thick films when grain growth is driven by strain energy minimization. The model also matches the experimental data concerning the grain size and film thickness dependences of the yield stress in polycrystalline Cu thin films either deposited on a substrate or freestanding. Interestingly, the yield stress is found to be fitted by a modified Hall–Petch relation resulting in a d − n dependence in which the exponent n varies between ½ and 1 as a function of the grain size for a given thickness. [Copyright &y& Elsevier]

In the scope of integrating III–V device contacts on a 300 mm platform, Ni-based contacts are envisioned. In this regard, the Pt redistribution in the Ni 0.9 Pt 0.1 /InP system, and the impact of Pt-alloying of Ni thin films on InP over solid-state reaction and layer morphology have been investigated. Results have shown that at low temperature (T < 300 °C), the presence of Pt partially slows down the diffusion of Ni towards the InP substrate, which as a result delays the growth of an intermixing amorphous Ni–In–P layer. In addition, the presence of Pt in the system has delayed the consumption of the Ni 0.9 Pt 0.1 layer. At higher temperatures (T ≥ 300 °C), the thermal energy brought to the system overcomes the Pt-induced partially slowed down Ni diffusion, and the observed phase formation sequence indicates that the Ni-based crystallized phases (Ni 2 P, Ni 3 P and Ni 2 InP) are identified regardless of the presence of Pt, which is not incorporated into the formed Ni-based phases (Ni 2 P, Ni 3 P and Ni 2 InP). Instead, the latter is rejected from the forming interface, which allows it to participate to the formation of the stable Pt 3 In 7 crystallized phase. [ABSTRACT FROM AUTHOR]

A methodology that allows the quantification of structural changes in functional thin films during the application of external electrical field is reported. The originality of this method is the development of a set-up using a laboratory X-ray source since most of previous Operando studies have used synchrotron radiations. Several technical challenges have been addressed: the (i) optimization of the electrical contact and the sample geometry within the lab-source goniometers, (ii) evaluation of any X-ray dose effect on the Metal/Insulator/Metal structure to prevent eventual charge accumulation at the electrode interfaces and (iii) the quantification of the effect of the time-delay, needed for X-ray measurement, on domain switching. The validity of our method has been demonstrated on a prototypic sol-gel lead zirconate titanate (PZT) thin film where the polarization and structural changes have been simultaneously measured. The evolution of ferroelastic domains as a function of external electric field has been quantified and two different effects have been successfully separated: (a) the cell extension and (b) domain wall motion described as the switching between a and c tetragonal domains. [ABSTRACT FROM AUTHOR]

Antiphase boundaries free GaSb epitaxial layers with low surface roughness (< 0.5 nm) have been synthesized on standard microelectronic 300 mm nominal (001)-Si substrates by metal organic chemical vapor deposition using a two-step growth process. By adjusting the growth temperature and the thickness of the nucleation layer, antiphase boundary free GaSb layers as thin as 250 nm are obtained. The 12% lattice mismatch between GaSb and Si is accommodated by both the formation of threading dislocations and a periodic array of 90° misfit dislocations at the interface. A GaSb layer inserted between AlSb barriers has been grown on an optimized GaSb/(001)-Si buffer layer and exhibits room temperature photoluminescence. [ABSTRACT FROM AUTHOR]

Using a metal-organic tungsten based precursor, a fluorine-free tungsten thin film has been obtained. The process deposition recipe includes a plasma-enhanced CVD (PECVD) step and atomic layer deposition (ALD) cycles. A set of physicochemical characterizations including X-ray reflectivity (XRR), in-plane X-ray diffraction (XRD), wavelength dispersive X-ray fluorescence (WDXRF), plasma profiling time of flight mass spectrometry (PPTOFMS) and microscope observations has been realized in order to study the W thin film structure and properties. The film is perfectly conformal whatever the structure size investigated (from tens of nanometers to micrometers wide). It was also highlighted that the F-free W film exhibits the lowest electrical resistivity phase ( α -W) but is not pure. Indeed, in addition to a top surface oxidation, a layer located at the W film / substrate interface is present. This interface layer (IL) contains impurities, including carbon and oxygen, due to ligand decomposition. This IL might be deposited during the soak step or during the PECVD step. The W liner with thicknesses ranging from 3 to 4 nm has been implemented on PCRAM structures in order to evaluate its impact on contact plug resistivity. First electrical results are promising and demonstrate the interest of using a F-free low resistance W liner. At the aspect ratio studied, the gain in terms of contact plug resistivity is about 20% compared to the process of reference using a TiN liner. Modeling shows that this benefit is mainly due to the reduction of interface resistances. [ABSTRACT FROM AUTHOR]

Highlights: [•] Phase sequence of solid state reactions of ultra-thin 7nm NiPt(10%) films with a Si0.7Ge0.3 layer. [•] In situ X-ray diffraction and sheet resistance (four point probes) measurements. [•] Hexagonal θ-(Ni1 − y Pt y )2(Si1 − x Ge x ). [•] Kinetics study by Kissinger analysis and finite difference simulations. [ABSTRACT FROM AUTHOR]

Abstract: High resolution diffraction measurements of the strained lattice unit of HgCdTe and CdZnTe have been performed at temperatures varying from room temperature to 300°C and for different lattice mismatch between substrate and layer. This investigation makes possible the determination of the coefficients of thermal expansion (CTE) and the evolution of the HgCdTe film stress during the thermal cycles. It is found that the CTE is linear with the zinc fraction for CdZnTe while it can be described by a parabolic variation as a function of the cadmium fraction for HgCdTe. The temperature evolution of the stress is found to be dictated by the CTE difference between substrate and layer up to a temperature of 150°C above which the HgCdTe layer partially relaxes. The evolution of the stress with lattice mismatch enables the determination of the onsets for plastic relaxation for both tensile and compressive stress. [Copyright &y& Elsevier]

[Display omitted] Hybridized focal plane array (FPA) HgCdTe (MCT) sensors are the workhorse of high performance infrared detectors covering a broad range of applications from space investigation to gas monitoring. Despite the improvements in the performance of these sensors in the last decades, device failure due to the lattice and thermal expansion mismatches between MCT and the Si readout circuit still affects the overall MCT detector performance. In this work, we use in-situ dark-field X-ray microscopy (DFXM) to map the structural variations of a fully operable MCT sensor at temperatures down to 80 K. We report, for the first time, on the nanoscale structural evolution over a large population of photodiodes at operating temperatures with high spatial and angular resolution. Our results show that lattice distortion and strain in the MCT epilayer increases at lower temperatures. The FWHM values of the rocking curves reach up to 0.02 ∘ at 80 K, three times higher than the room temperature value. The thermal cycle results show that the thermal effects are almost completely reversible and the measured strain is in the elastic regime. We discuss the origin of the temperature-generated structural modifications using complementary finite element modelling. [ABSTRACT FROM AUTHOR]

Abstract: The functionality and lifetime of thin film/substrate set depend mainly on its mechanical properties. Probing and improving the thermo-mechanical behaviour (stability) are then of utmost importance. Amorphous carbon thin films, 320 nm thick, have been deposited by a sputtering technique on silicon wafers, 500 and 200 μm thick. The microstructure and the mechanical properties (hardness, indentation reduced modulus and average in-plane stresses) have been investigated using Raman and infrared spectroscopies, silicon curvature and nanoindentation experiments. In particular, the evolution of global stress in the film has been analysed in situ during an annealing treatment while the evolution of the mechanical response (elastic and plastic) induced by nitrogen post irradiations was surveyed by nanoindentation. We observed a rather good thermal stability of the film/substrate set and the presence of hydrogen in the film is discussed. Further, nitrogen irradiation and incorporation were observed to induce a dramatic decrease of the mechanical performance of the films. These behaviours are discussed in view of the thin film structure. [Copyright &y& Elsevier]

• Isolated molten island are formed at the onset of melt. • The liquid/solid interface remains rough in partial melt regime. • Relaxation is linked to liquid/solid interface roughness. • Relaxation is linked to the elastic energy stored in SiGe layers. 30 nm-thick pseudomorphic Si 1−x Ge x layers with Ge concentrations x ranging from 0 to 0.4 were submitted to Ultraviolet Nanosecond Laser Annealing (UV-NLA). The impact of UV-NLA on the various regimes and on the layer crystallinity was assessed for each Ge concentration. This study highlighted the existence of four annealing regimes, with notably a surface melt regime with isolated molten islands on the surface. The strain in the layer depended on the liquid/solid interface roughness and on the stored elastic energy in the layers. In the case of smooth liquid/solid interfaces, a limit for perfect recrystallization was estimated near 750 mJ/m2. [ABSTRACT FROM AUTHOR]

The development of Complementary Metal Oxide Semiconductor (CMOS)-compatible contact technology on III–V materials based on Ti for electronics or photonics applications was studied. In this framework, solid-state reactions between Ti thin films (20 nm) and In 0.53 Ga 0.47 As layers grown on InP substrates were studied from the as-deposited state up to 550 °C using a combination of advanced X-ray diffraction (in-plane reciprocal space mapping), Auger electron spectroscopy and transmission electron microscopy analyses. The phase formation sequence was solved. At low temperature, an amorphous Ti–Ga–As intermixing layer coexists with the Ti film. As of 250 °C, the first crystalline phase to form is Ti 2 Ga 3. At 300 °C, a new crystalline phase appears, namely TiAs 2. On the other hand, TiAs and metallic In form at 350 °C and Ti is completely consumed between 450 and 500 °C. The diffusion of the various species lead to the formation of a non-nominal Ga-rich In x Ga 1−x As layer and at 550 °C to the formation of polycrystalline GaAs. Ti was found to be the main diffusing species at low temperature whereas III and V elements are the dominant diffusing species at higher temperatures. The nature of the phases formed above and below the original Ti/InGaAs interface might explain the In accumulation at the interface, the TiAs phase acting as a diffusion barrier. [ABSTRACT FROM AUTHOR]