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We report experimental results obtained for electrical and structural characteristics of yttria-stabilised zirconia (YSZ) thin films deposited by pulsed laser deposition (PLD) on Si substrates at room temperature. Some samples were submitted to thermal treatments in different ambient atmospheres (vacuum, N 2 and O 2 ) at a moderate temperature. The effects of thermal treatments on the film electrical properties were studied by C – V and I – V measurements. Structural characteristics were obtained by X-ray diffraction (XRD), X-ray reflectivity (XRR) and transmission electron microscopy (TEM) analyses. The as-deposited film was amorphous with an in-depth non-uniform density. The annealed films became polycrystalline with a more uniform density. The sample annealed in O 2 was uniform over all the thickness. Electrical characterisation showed large hysteresis, high leakage current and positive charges trapped in the oxide in the as-deposited film. Post-deposition annealing, especially in O 2 atmosphere, improved considerably the electrical properties of the films.

Hydrogen storage in composite materials is a feasible way to overcome the main drawbacks of the metal hydride systems. In the present paper, we report on the hydrogenation properties of three polydimethylsiloxane (PDMS)–palladium composite samples with different content of metallic fraction (5, 15, 50 in wt.%). Hydrogenation tests in different conditions of temperature and pressure were performed using a Sievert's type apparatus, while the microstructure of the samples was characterised by means of scanning electron microscopy observations and X-ray diffraction measurements. Results show that the hydrogen storage capacity is inversely proportional to the metallic content in the composite samples.

Experimental evidence of the anisotropy in the hot-hole drift velocity v d of Si between 300 and 430°K has been theoretically proved to be strongly correlated to the warped shape of the heavy valence band. The comparison between theory and experiments permits a valuable check on the competitive role played by the strong nonparabolicity of the Si valence band and the lattice scattering mechanisms.

Electron drift velocity in silicon is studied at and above room temperature (300, 370 and 430 K) as function of field strength (up to 60 kV cm ) and orientation (〈111〉 and 〈100〉). Experimental data show a small anisotropy even at the highest considered temperature, while saturation is well evidenced only at 300 K with the field oriented along the (111) axis. The data are interpreted with theoretical Monte Carlo calculations. The model includes non-parabolicity of the band, and a non-parabolicity parameter α = 0.5 eV−1 is suggested by the comparison of theoretical and experimental results.

The AuAl compound was obtained by low temperature (190–250°C) heat treatment of a thin gold and aluminium film. The compound was identified by X-ray diffraction and its thickness was measured by 4He MeV ion backscattering. The AuAl layer grows at a fixed temperature as a function of (time)12. The activation energy of the growth compound is 1.2 eV. This compound is stable up to the maximum investigated temperature (≈500°C).

Uniform epitaxial growth has been obtained by dissolution and transport of an evaporated Si film through an evaporated Al film at temperatures below 500°C. By analyzing the samples made in different ways we show that the presence of a cap on the metal layer, which inhibits the diffusion of the metal through the evaporated Si, plays a fundamental role. The cap consists of a thin oxide layer grown on top of the metal. The cap is made by leaving the sample in vacuum for two days or by heating the sample in vacuum before the Si deposition. The study of the initial growth rate on 〈100〉 and 〈111〉Si substrates reveals that the growth starts as islands which grow until they coalesce to form a continuous layer. Different growth rates have been obtained by using 〈100〉 and 〈111〉Si substrates. Typical growth rates are 50 A/min at 330°C on 〈100〉 and 100 A/min at 392°C on 〈111〉. The activation energy of the process is 1.2 eV.

All the compounds predicted by SiPt phase diagram have been observed by depositing thin layers of Pt on Si in known quantities and ratios to each other by using an unreactive substrate. Emphasis is given to Pt6Si5 and Pt12Si5 formation. They are two new binary compounds which we have experimentally identified for the first time in planar thin film reaction. 4 He + backscattering and X-ray diffraction techniques have been used to analyse the formation of the compounds obtained by thin film deposition and annealing in 200–750°C temperature range. The phases appearance with increasing temperature exhibits a pattern which sequence is presented taking into account the formation temperature and the heat of reaction.

The growth of PdGe and Pd2Ge compounds was investigated by analyzing, after annealing, samples with about 1000–3000 A thick evaporated Pd, using either bulk (single-crystal) Ge or amorphous (evaporated) Ge as substrate. The growth rate is different in both cases. The grain sizes of each compound, as determined by X-ray diffraction line-broadening, are the same for both Ge substrates. Therefore the hypothesis of formation processes controlled by grain boundary diffusion seems invalid. A different mechanism is suggested.

The interaction of Ni film deposited on Si has been studied. Growth kinetics of NiSi on (111) and (100) silicon single crystals are reported. Activation energies for NiSi are found to be 1.23 eV for (100) and 1.83 eV for (111).

Anisotropic effect of the hole drift velocity in silicon and germanium has been investigated with the time of flight technique by applying the electric field parallel to the

Solid phase epitaxial growth has been obtained by annealing at temperatures below 500°C the structures 〈111〉 Si/evaporated Al/evaporated Si. The transport and the growth of the Si has been studied by SEM, electron microprobe, He + backscattering and channeling effect measurements. To study the growth process the structures were heated at different temperatures and times. The initial stage of epitaxial growth is laterally non-uniform and assumes an island structure. The islands grow laterally to form a uniform epilayer in the final stage. The quantity of Si transported through the Al increases linearly with time and at 392°C the transport rate is about 100 A/min. The activation energy of the crystallization process in the 363–413°C temperature range is 1.2 ± 0.1 eV. Al inclusions, found in the epi-grown layer, are preferentially localized at the 〈111〉 Si-growth interface.

Switching effects have been studied in high resistivity undoped β-rhombohedral boron in the temperature range 77 to 400°K using electrical and electro-optical measurements. The data collected must be interpreted with different models describing the origin of the switching action, i.e. double injection at low temperatures (about 77 to 250°K) and thermal instability at higher temperatures (250 to 400°K). A description of the main physical events giving rise to switching for double injection in the investigated sample is given. Emission of infrared radiation in the postswitching regime due to hole—electron recombination is also reported.

The reflectivities of Pd and Pd silicides have been measured from 0.5 to 6 eV and compared with the existing density of states and band calculations as well as with the optical spectra of other silicides. The rather complex spectra resulting from the superposition of the free carrier response and inter-band transitions are discussed and some indications concerning their interpretation are drawn.

The drift velocity of electrons in silicon has been measured over a wide range of electric fields (from 3×102 to 6×104 V/cm) at temperatures of up to 430 K. The experimental data have been fitted to a simple formula for the temperatures of interest. The mean-square deviation was, in all cases, less than 3·8%.

We report on the deposition of thin Yttria-stabilized zirconia (YSZ) films and TiN/YSZ bilayers on Si substrates at room temperature by pulsed KrF excimer laser ablation deposition (PLD). YSZ films were deposited onto (1 0 0) Si substrates by ablating an YSZ target in vacuum and in low-pressure oxygen atmosphere. TiN/YSZ/Si bilayers were deposited in two steps without exposure to the air using a multitarget system: first, an YSZ film was deposited onto a Si substrate by ablating an YSZ target in oxygen ambient gas, then a Ti target was ablated in nitrogen ambient gas. Morphological and structural characteristics were investigated by Rutherford backscattering spectrometry (RBS), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray reflectivity (XRR) techniques.

The interface reactions in Co/W multilayers (ML) with Co thickness of 1 and 2 nm and W thickness of 1, 2 and 5 nm in as-deposited state and under KrF laser irradiation with fluences F=50–200 mJ/cm2 were studied by different X-ray methods. Superlattice satellites around W (1 1 0) direction were found in as-deposited and irradiated multilayers. The layered structure persists up to the highest applied fluence. Co3W compound is formed at the interfaces. However, the intermixing is low.

We report on the deposition of thin vanadium nitride films by ablating vanadium targets in low-pressure N 2 atmosphere, and on their characterization. The targets were vanadium foils (purity 99.8%). 3 in. Si(1 1 1) wafers were used as substrates. Film characteristics (composition and crystalline structure) were studied as a function of N 2 pressure (0.5–200 Pa), KrF laser fluence (4.5–19 J/cm 2 ), substrate temperature (20–750 °C) and target-to-substrate distance (30–70 mm). Vanadium nitride is already formed at low N 2 ambient pressures (1 Pa) and laser fluences (6 J/cm 2 ) on substrates at room temperature. At the N 2 pressures of 1–10 Pa, the prevalent phase is VN. At higher pressures (100 Pa) and at relatively high laser fluences (16–19 J/cm 2 ), the dominant phase is V 2 N. The crystallinity of the films improves by increasing the substrate temperature. Well-crystallized films are obtained on substrates heated at 500 °C.

Titanium carbide films were deposited on silicon wafers by XeCl (308 nm) excimer laser ablation of titanium in low pressure (10 -6 -10 -1 mbar) methane atmosphere. Series of 10 000 pulses at the repetition rate of 8 Hz were directed to the target surface. The fluence was set at 4.5 and 5.5 J/cm 2 . Pulse duration was about 30 ns. The deposited films were charcterized by different techniques (Rutherford backscattering spectrometry, X-ray diffractometry and scanning electron microscopy). Results show that at both fluences and at pressures below ∼ 10 -5 mbar the deposited films are mainly formed of metallic titanium. In the range 10 -3 -10 -1 mbar, at the fluence of 4.5 J/cm 2 , the deposits are formed of titanium carbide (TiC) with only traces of oxides. At the fluence of 5.5 J/cm 2 the amount of ablated material is too large to undergo complete reaction and mostly metallic titanium is deposited.

Titanium and silicon nitride films were deposited on silicon wafers by XeCl (308 nm) excimer laser ablation of titanium and silicon, respectively, in low pressure (10 −3 −5 mbar) nitrogen-containing atmospheres. Series of 10 000 pulses at a repetition rate of 10 Hz were directed to the target surface. The fluence was set at about 5 J/cm 2 . Pulse duration was about 30 ns. The deposited films were characterized by different techniques (X-ray diffraction, scanning and transmission electron microscopy, etc.). Good quality films with a thickness exceeding 1 μm were obtained under specific experimental conditions.

The growth of high-mobility modulation-doped Si/SiGe heterostructures on silicon-on-insulator (SOI) substrates is demonstrated. The structural and electrical properties of the samples are comparable with those of similar samples grown on standard Si substrates. Electron mobilities as high as 2800 cm 2 V −1 s −1 at room temperature and 8.2×10 4 cm 2 V −1 s −1 at 4 K are obtained.

The thermal stability of e-beam deposited multilayers (MLs) for soft X-ray reflection optics was studied under XeCl laser processing in vacuum. MLs with five Co/Si/W/Si periods, each 13.5 nm (MLS1) or 18.4 nm (MLS2) were deposited onto oxidized Si and irradiated at the fluences of 0.075–0.62 J cm −2 by 1 or 100 pulses. The samples were analyzed by X-ray diffraction, hard X-ray reflectivity and sheet resistance measurements. The layered structure of our samples persists up to 0.62 J cm −2 per 1 pulse for MLS2 and 0.62 J cm −2 per 100 pulses for MLS1 irradiations. The thermal stability of MLS1 is even better than for W/Si MLs studied previously. In laser irradiated samples the Co 2 Si 3 phase which is normally formed under high pressures (>4 GPa) was found. It has not been reported in the film couples so far. The high thermal stability and Co 2 Si 3 formation in MLS1 are explained by complex Co–Si silicide formation conditions and compressive stress parallel to the surface of irradiated samples.

Silicon carbide films were deposited on Si wafers (at room temperature and 150°C) by XeCl laser (fluence 5 J/cm2, pulse duration 30 ns, repetition rate 10 Hz) ablation of Si in low pressure (0.25–6 mbar) CH4 atmosphere. The deposits were characterized by different diagnostic techniques (XRD, XPS, RBS, etc.). Polycrystalline stoichiometric silicon carbide films ∼ 1 μm thick were obtained under specific conditions after ∼ 104 laser pulses.

Silicon nitride films were deposited on silicon wafers by XeCl (308 nm) excimer laser ablation of silicon in low pressure (1 × 10 −3 −1 mbar) ammonia atmospheres. Series of 10000 pulses at the repetition rate of 8 Hz were directed to the target surface. The fluence was set at about 5 J/cm 2 . Pulse duration was about 30 ns. The deposited films were characterized by different techniques (X-ray diffraction, infrared spectrophotometry, X-ray photoelectron spectroscopy, Auger electron spectroscopy, scanning electron microscopy, profilometry). Deposition of stoichiometric silicon nitride films with thickness close to 1 μ m (deposition rate ∼ 0.1 nm/pulse) was obtained when ablation was performed in ammonia at the pressure of 1 mbar.

The formation of tungsten silicide induced by XeCl laser irradiation of W(150 nm)/Si and W(500 nm)/Si samples was studied at laser fluences ranging from 0.6 to 1.8 J/cm 2 . Up to 300 subsequent laser pulses were directed to the same irradiation site. After irradiation the samples were examined by different diagnostic techniques: Rutherford backscattering spectroscopy, X-ray scattering, resistometry and surface profilometry. Complete reaction of the 150 nm W film with silicon was obtained between 30 and 100 laser pulses at the fluence of 1.2 J/cm 2 , and after 30 laser pulses and at the fluence of 1.5 J/cm 2 . The sheet resistance of these silicides was 5–10Ω. At the used fluences, only the onset of silicide synthesis at the W-Si interface was observed for the 500 nm W film. Numerical computations of the evolution and depth profiles of the temperature in the samples as a consequence of a laser pulse were performed and compared to the experimental results.

We report a study of the formation of nitride surface layers on titanium foils by multipulse (100 to 2500) XeCl excimer laser (λ = 308 nm) irradiation in N2 and NH3 atmosphere. After irradiation the samples were analyzed by Rutherford backscattering spectroscopy (RBS) and nuclear reaction analysis (NRA) and then examined by electron microscopy (SEM, TEM). The nitridation process was shown to be very efficient with both gases. The amount of nitride has been observed to depend on the number of subsequent laser pulses, on the pulse repetition rate and on the nature of the ambient gas.

Polycrystalline SiC layers were obtained through pulsed annealing of thin (100 nm) carbon films deposited on single-crystalline silicon wafers. The samples were submitted to electron beam irradiation (25 keV, 50 ns) at various current densities in vacuum (∼10 −4 mbar) and to XeCl excimer laser pulses (308 nm, 15 ns) in air. Rutherford backscattering analysis showed that in the e-beam annealed samples mixing of the elements at the interface starts at current densities of about 1200 A/cm 2 . The mixed layer thickness increases almost linearly with current density. At current densities higher than 2400 A/cm 2 ablation of the C film was always observed. Using the XeCl excimer laser, a good intermixing of the deposited C film with the Si substrate was observed after a single 0.3 J/cm 2 pulse. From the RBS spectra a composition of the intermixed layers close to the SiC compound was deduced. Transmission electron microscopy and electron diffraction studies clearly evidenced the formation of SiC polycrystals.

Carbon nitride films were deposited at 20, 250 and 500°C on 〈111〉 Si substrates by XeCl laser ablation of graphite in low pressure (1–50 Pa) N2 atmosphere at fluences of 12 and 16 J/cm2. Different diagnostic techniques (SEM, TEM, RBS, XPS, XRD) were used to characterize the deposited films. Films resulted plane and well adhesive to their substrates. N/C atomic ratios up to 0.7 were inferred from RBS measurements in films deposited at 20°C and 16 J/cm2. Nitrogen concentration increases with increasing ambient pressure and laser fluence. The N 1s peak of the XPS spectra indicate two different bonding states of nitrogen atoms to C atoms, while the C 1s peak, apart from the two bonding states to nitrogen atoms, indicates one bonding state with regard to carbon atoms. XRD and TEM analyses point to an oriented microcrystalline structure of the films. Heating of the substrate results in a lower nitrogen concentration in respect of films deposited at 20°C in otherwise identical experimental conditions. Optical emission studies of the laser plasma plume indicate a correlation between the emission intensity of the CN radicals in the plume and the nitrogen atom concentration in the films.