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The structure and morphology of chromium disilicide (CrSi2) nanometric films grown on 〈1 0 0〉 silicon substrates both at room temperature (RT) and at 740 K by pulsed laser ablation are reported. A pure CrSi2 crystal target was ablated with a KrF excimer laser in vacuum (∼3 × 10−5 Pa). Morphological and structural properties of the deposited films were investigated using Rutherford backscattering spectrometry (RBS), grazing incidence X-ray diffraction (GID), X-ray reflectivity (XRR), scanning (SEM) and transmission electron microscopy (TEM). From RBS analysis, the films’ thickness resulted of ∼40 nm. This value is in agreement with the value obtained from XRR and TEM analysis (∼42 and ∼38 nm, respectively). The films’ composition, as inferred from Rutherford Universal Manipulation Program simulation of experimental spectra, is close to stoichiometric CrSi2. GID analysis showed that the film deposited at 740 K is composed only by the CrSi2 phase. The RT deposited sample is amorphous, while GID and TEM analyses evidenced that the film deposited at 740 K is poorly crystallised. The RT deposited film exhibited a metallic behaviour, while that one deposited at 740 K showed a semiconductor behaviour down to 227 K.

RE 1 Ba 2 Cu 3 O 7-δ (RE = Er or Y) superconducting films were fabricated by reactive laser deposition, in situ, on YSZ(100), SrTiO 3 (100) and Si(001), under various conditions. A complete XRD investigation showed that the films grown with high substrate temperatures (T s > 740°C) combined with low fluences (1.5 J / cm 2 < 2 J / cm 2 ) and laser repetition rate (4 Hz) have the best structural characteristics, very good electrical and magnetic properties.

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.

Silicon-nitride films were deposited on silicon waters by XeCl (308 nm) excimer-laser ablation of silicon in low-pressure (0.05–5 mbar) ammonia atmospheres. Series of 10 000 pulses at the repetition rate of 8 Hz were directed to the target surface. The fluence was set at about 5 J/cm2. Pulse duration was about 30 ns. The deposited films were characterized by different techniques (X-ray diffraction, X-ray photoelectron spectroscopy, Auger electron spectroscopy, Rutherford backscattering spectrometry, scanning electron microscopy, profilometry). Silicon-nitride films with thickness close to 1 μm were obtained under specific experimental conditions.

We report on the deposition of thin titanium carbide films on 60 mm and 100 mm Si wafers by KrF laser ablation of titanium targets in low-pressure (0.1 Pa) CH 4 and C 2 H 2 atmospheres, and on their characterization. The targets were titanium foils (purity 99.6%). Si (111) wafers, 60 and 100 mm in diameter, were used as substrates. Film characteristics (thickness, composition and crystalline structure) were studied as a function of the carbon-containing gas (C 2 H 2 or CH 4 ), laser fluence (4 or 6 J/cm 2 ), substrate temperature (20 or 250 °C) and target-to-substrate distance (70–120 mm). Continuous, well adhesive polycrystalline TiC films were deposited even without any heating of the substrate. Films deposited in C 2 H 2 ambient atmosphere are better crystallized and less prone to surface oxidation with respect to films deposited in CH 4 atmosphere, in otherwise identical conditions.

Cd 1− x Mn x Te films (0.5–0.6 μm) were deposited on sapphire and silicon substrates by XeCl laser ablation of targets with different Mn content ( x =0.05, 0.36 and 0.43). Energy dispersive spectroscopy and optical transmission measurements in the 200–3500 nm range were performed to evaluate the film composition and band-gap energy. The film stoichiometry resulted in quite good agreement with one of their relative targets. Scanning electron microscopy inspection showed that the surface morphology is good for films with low Mn concentration ( x =0.05), but it deteriorates with increasing Mn concentration. From photoluminescence spectroscopy only the peak at ∼2.0 eV, associated to the Mn 2+ 4 T 1 → 6 A 1 transition, was detected in samples with x ≥0.36.

We report on the pulsed laser deposition (PLD) of thin films of chalcogenide and tellurite glasses doped with RE ions. The depositions were performed in vacuum, for chalcogenide films, and in a low oxygen pressure for the tellurite films by using an excimer laser. After the deposition, the morphological, structural, optical and spectroscopical characteristics are analysed by different techniques: Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Rutherford Backscattering Spectrometry (RBS), optical profilometry, m-lines spectroscopy, photoluminescence etc. The experimental results demonstrated that PLD is a suitable technique for the realisation of films of complex materials for optoelectronic and photonic applications.

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.

This paper describes the optical properties of praseodymium-doped chalcogenide (GeS 2 –Ga 2 S 3 –CsI) thin films deposited by the pulsed laser deposition (PLD) technique using XeCl (308 nm) and KrF (248 nm) excimer lasers. Optical transmission and reflection spectra, at normal incidence, were recorded in the 200–2500 nm spectral region. The optical constants (refractive index n and extinction coefficient k ) versus wavelength, as well as the film thickness, were calculated from these spectra and a computer code. The waveguiding properties of the deposited films were investigated by the prism coupling technique (m-lines spectroscopy). The presence of praseodymium in the doped chalcogenide thin film was analysed by exciting the electrons to the 1 G 4 level and collecting the photoluminescence spectrum in the 1.335 μm region. Moreover, compositional, morphological and structural characteristics of the films were obtained by Rutherford backscattering spectrometry (RBS), scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses.

Ag/Co bilayers and Co/Ag/Co trilayers were studied in order to extend our previous results on the excimer laser-induced grain boundary diffusion in Ag/Co layered structures, used in giant magnetoresistance devices. The e-beam deposited structures were processed by KrF excimer laser at the fluences F =0.1–0.25 J cm −2 with 1–1000 pulses. The temperature and depth of melting vs. time evolutions were computed for the first laser pulse. Samples were studied by X-ray reflectivity (XRR), X-ray diffraction (XRD), grazing incidence XRD, Rutherford backscattering spectrometry (RBS) and resistometry. The intermixing phenomena at the Ag/Co solid–solid, liquid–solid and liquid–liquid interfaces were quantitatively characterized. It was shown that in the immiscible Ag/Co combination of metals the interfaces could become sharper under laser processing, probably due to the back-diffusion effect.

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.

A hexagonal-BN target was ablated by high-fluence (6 and 12 J/cm2) KrF excimer laser pulses in low-pressure (5 Pa) N2 atmosphere, without any aid of ion bombardment and heating of the Si substrate. Investigations of the deposited films show that the cubic-BN phase was deposited. The film deposited at 6 J/cm2 appears to contain a higher cubic phase content with respect to the one deposited at 12 J/cm2.

Carbon nitride films, deposited on < 111 > Si substrates at room temperature by XeCl laser ablation of graphite targets in low pressure (1, 5, 10 and 50 Pa) N-2 atmosphere at the fluence of 16 J/cm(2) (similar to 0.5 GW/cm(2)) have been submitted to accurate X-ray photoelectron spectroscopy (XPS) investigations in order to study the C-N chemical bonding in the films. Multiple binding energy values have been obtained. The N 1s peak of the XPS spectra indicates three different binding states of nitrogen atoms to C atoms, while the C 1s peak, apart from the binding states to nitrogen atoms, indicates other bonding states with regard to carbon atoms.

Co/Ag/Co trilayers were studied in order to confirm our previous results on the laser irradiation improvement of GMR ratio in immiscible Ag/Co multilayers (MLs). E-beam deposited samples were processed by XeCl excimer laser at the fluenees F = 0.15, 0.2, 0.3 and 0.36 J/cm 2 with n = 1−100 pulses of 30 ns duration. The temperature versus time evolutions were computed for the first laser pulse. Samples were studied by grazing incidence XRD, RBS and resistometry. From results it follows that grain boundary diffusion of Ag across Co layers going through even during short irradiation times, may be the explanation of GMR improvement via transformation of continuous ML into discontinuous one.

The effects of high laser fluence on the properties of CN x thin films prepared by reactive pulsed laser (KrF excimer laser, λ =248 nm, τ FWHM =30 ns) ablation at two different N 2 gas pressures were investigated. A variety of analytical techniques have been used to characterize the structure and properties of the deposited films: X-ray photoelectron spectroscopy; X-ray diffraction; scanning electron microscopy; energy dispersive X-ray spectroscopy; Fourier transform infrared; and Rutherford backscattering spectroscopy. Analysis of these data shows the existence of a certain amount of covalent C–N single bonds and a nitrogen content up to 44%. The results also show the presence of covalent C≡N triple bonds in the film deposited at high nitrogen pressure (50 Pa). Comparison with the films deposited by XeCl excimer laser ( λ =308 nm, τ FWHM =30 ns), at the same experimental conditions, will also be presented.

The structural, electrical, and optical characteristics of nanometric Fe2O3−x films fabricated on ⟨100⟩ Si and SiO2 substrates by ablating an iron target with a KrF excimer laser in low pressure (0.05–1.0 Pa) O2 atmosphere are reported. The thickness of films fabricated with 4000 laser pulses is ∼80 nm for samples deposited at the lowest pressure (0.05 Pa) and decreases gradually to 50 nm at the highest used pressure (1.0 Pa). The film mean composition results close to FeO at lower pressures (0.05–0.10 Pa) and to Fe2O3 at higher pressures (0.5–1.0 Pa). From glazing incidence x-ray diffraction spectra, it was inferred that deposits are poorly crystallized, especially the ones prepared at relatively high oxygen pressures (0.5–1.0 Pa). Scanning electron microscopy inspections show that surfaces are plane and uniform, with very rare (

We present experimental results obtained for R Ba 2 Cu 3 O 7 − x ( R = Y,Er) expitaxial thin films obtained through pulsed laser deposition (PLD) and grown on yttria stabilized zirconia (YSZ) and SrTiO 3 (STO) substrates. The films have been deposited by using low deposition rates ( f = 4 Hz) and with control of the film surface temperature rather than that of the sample holder leading to a high quality of the epitaxy.

Carbon nitride films were deposited at room temperature on 〈111〉 Si substrates by XeCl laser ablation of graphite in low pressure (1–50 Pa) N2 atmosphere at a fluence of 12 J/cm2. N/C atomic ratios up to 0.5 were inferred from Rutherford backscattering measurements. Different diagnostic techniques (ARXPS, FTIR transmission spectroscopy, EDS, SEM and XRD) were used to characterize the deposited films. XRD spectra indicate a polycrystalline structure of the films.

The optical response of 200 nm thick La0.7Sr0.3MnO(3 - delta) films, deposited by pulsed laser deposition on amorphous silica substrates heated at nearly 600 degrees C, under different oxygen pressures (0.1 Pa, 0.5 Pa, 1 Pa, 5 Pa and 10 Pa), is reported. The effects of the oxygen non-stoichiometry are investigated at room temperature dealing with the absorption coefficient and the Tauc's plot method rather than conventional optical conductivity. The absorption curves are evaluated by an algorithm able to realistically describe the behavior of thin films without exploiting numerical extrapolations or simplified theoretical models or ab-initio calculations. Optical features, tunable by the growth oxygen pressure, are discussed based on the known theoretical and experimental scenario. (C) 2013 Elsevier B.V. All rights reserved.

The design of the injection and bunching section for a Sub-millimetric klystron is described in this paper. A Carbon nanotube cold cathode is employed to produce the required beam current. An opportune shape of the device has been chosen to allow for the micro-fabrication, while ensuring the correct Buncher excitation. In this range of critical dimensions, multiple physics influencing factors, due to the heating effects and power dissipations over the beam dynamics, may alter the desired behavior of the device. A multiphysics design approach has been employed to ensure the future correct operation selecting appropriate materials and shapes. Several strategies have been adopted to obtain a simple but reliable model.

High quality ErBa2Cu3O7−x thin films were grown by reactive laser deposition on yttria‐stabilized zirconia substrate. The structural and electrical properties of the samples were investigated by x‐ray double‐crystal diffractometry, texture analysis and reciprocal space mapping, and resistivity measurements, respectively. The best films were obtained by using high substrate temperature combined with a low fluence and low laser repetition rate. In these conditions the deposition rate results were very low, namely

Mo/Cu multilayered metallizations with ≤ 10 Cu conducting layers of various thicknesses separated by Mo diffusion barriers 20 nm thick were deposited by magnetron sputtering onto oxidized Si wafers. The samples were annealed for 1 h in the vacuum of 10−3 Pa at temperatures between 400°C and 800°C and in a N2 atmosphere at temperatures up to 700°C Rutherford backscattering spectroscopy, X-ray diffraction in both standard and grazing incidence configurations, scanning electron microscopy, electron diffraction spectroscopy and resistometry were employed to analyse the samples. Two mechanisms are assumed to be responsible for intermixing in immiscible Mo/Cu multilayers: grain boundary diffusion and the formation of Mo and Cu nitrides in nitrogen environment. In the nitrogen ambient the multilayer intermixed completely even at 500°C. In vacuum the 20 nm thick Mo layer was found to be an effective barrier against Mo/Cu intermixing up to 600°C/1 h annealing. Only a small increase (≤20%) of the multilayer resistance was recorded in the samples annealed in vacuum. Cu-enriched hillocks appeared on the surfaces of samples annealed at ≥ 500°C

Angular resolved X-ray induced photoelectron spectroscopy (ARXPS) and infra-red (IR) absorption measurements have been performed on carbon nitride layers deposited on Si(100) wafers kept at room temperature by an excimer laser ablation of graphite in nitrogen or ammonia. Results of both methods confirm the formation of carbon nitride with a graphite-like structure.

Matrix-Assisted Pulsed Laser Evaporation (MAPLE) technique was used to deposit films of Poly(9,9-dioctylfluorene) – PFO and Methoxy Ge Triphenylcorrole [Ge(TPC)OCH3]. The PFO was dissolved in different matrices, like chloroform-CHCl3, tetrahydrofuran – THF and toluene with a 0.5 wt % concentration, while Ge(TPC)OCH3 was diluted in THF with a concentration of 0.01 wt %. The frozen targets were irradiated with a KrF excimer laser. The, films presented good emission properties to be exploited in light emitting devices and gas sensors based on luminescence quenching. The working principle of the MAPLE technique was used for the deposition of colloidal nanoparticles and nanorods, too. TiO2 colloidal nanoparticles (diameter: ∼10 nm) and nanorods (diameter: 5 nm; length: 50 nm) were diluted in deionised water (0.02 wt %) and toluene (0.016 wt %) respectively. The deposited nanostructures preserved dimensions and structural properties of the starting particles and the films showed very interesting electrical responses when exposed to oxidizing gases for sensing applications.

Pb 100− x Co x , x =0, 9, 25, 32 and 36 at.% films composed of mutually immiscible metals were codeposited by two electron beam sources in UHV system at the SiO 2 /Si substrate temperature of 40°C. The samples were processed by XeCl excimer laser irradiation at the fluences F ≤0.2 J/cm 2 and number of pulses n =1, 10, 100 and 1000. The samples were analyzed by X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), EDAX/SEM and by resistometry. In the films fcc Pb was found. Neither fcc nor hcp Co were detected. From RBS analyses it follows that in Pb–Co films Co segregates at the surface, even in the as-deposited state. This distribution of concentration remains almost unchanged after laser irradiation. The porosity of Pb–Co films was considerably suppressed by laser irradiation in the melting regime.

We have deposited TiAlN films by using the reactive laser ablation technique. TiAl targets were ablated in low-pressure N2 (0.1–10 Pa) atmosphere by 2×104 XeCl excimer laser pulses at the repetition rate of 10 Hz. The laser fluence at the target was set at 6 J/cm2, corresponding to a power density of 0.2 GW/cm2. The films were deposited on Si substrates at room temperature, placed at 40 mm from the target. Their characteristics were investigated by many different techniques. Scanning electron micrographs show that surfaces are plane without cracks or corrugations. From Rutherford backscattering spectra it results that the thickness vary from ∼100 nm for films deposited at 0.1–0.5 Pa to 50 nm for the film deposited at 10 Pa. The mean composition is close to TiAlN for the film deposited at 0.1 Pa and close to TiAlN2 for the film deposited at 0.5 Pa. X-Ray diffraction analysis points to an amorphous structure of the film deposited at the lowest pressure (0.1 Pa), while peaks of fcc TiN and hexagonal Ti3Al2N2 appear in the spectra of the films deposited at higher N2 pressures. The complex chemical bonding of the top surface layer of the films was studied by X-ray photoelectron spectroscopy.

Matrix-assisted pulsed laser evaporation (MAPLE) was used to deposit layers of poly(9,9-dioctylfluorene) (PFO) to study the relation between the solvent properties (laser light absorption, boiling temperature and solubility parameters) and the morphology of the deposited films. To this end, the polymer was diluted (0.5 wt%) in tetrahydrofuran—THF, toluene and toluene/hexane mixtures. The thickness of the films was equal to 70 ± 20 nm. The morphology and uniformity of the films was investigated by Atomic Force Microscopy and by the photoluminescence emission properties of the polymer films, respectively. It is shown that, although the solubility parameters of the solvents are important in controlling the film roughness and morphology, the optical absorption properties and boiling temperature play a very important role, too. In fact, for matrices characterized by the same total solubility parameter, lower roughness values are obtained for films prepared using solvents with lower penetration depth of the laser radiation and higher boiling temperatures.

We have designed and built an ultra-high vacuum chamber which allows thin film deposition on large area (up to 100 mm diameter) flat substrates and on three-dimensional substrates (e.g. 100 mm long, 50 mm diameter cylinders) by the pulsed laser deposition and reactive pulsed laser deposition techniques. Heating of substrates during and after film deposition is possible using either resistive heaters or a lamp array. Metal (Cu) and metal nitride (TiN) and carbide (TiC) films were deposited on Si wafers (60 and 100 mm diameter), three-dimensional steel substrates (steel cylinders and screws), Teflon plates, and paper sheets.

Experimental results are reported concerning the synthesis of pure, hard, and adherent titanium nitride layers by multipulse excimer (λ=308 nm) laser irradiation in a nitrogen or ammonia atmosphere. It is shown that the process is more efficient when the irradiation is performed in a nitrogen atmosphere. The general characteristics of synthesized surface compound layers are compatible with the requirements of utilization in microelectronics.

Fe x Ni 100-x nanometric films were deposited on SiO 2 /Si substrates at room temperature using the pulsed laser deposition technique. The targets were Fe-Ni amorphous magnetic foils with composition Fe 50 Ni 50 , Fe 35 Ni 65 and Fe 22 Ni 78 Morphological and structural properties of the deposited films were investigated using scanning electron microscopy, Rutherford backscattering spectrometry, grazing incidence X-ray diffraction, and X-ray reflectivity. Electrical and magnetic characteristics of the films were investigated by using the four-point probe and the magneto-optic Kerr effect techniques, respectively. The film properties are strictly dependent on the Fe-Ni compositional ratio.

Narrow band gap iron oxide semiconductor films were grown with the laser chemical vapour deposition (LCVD) and reactive pulsed laser deposition (RPLD) techniques. For LCVD, 10 and 18 nm thick films, with composition Fe2O3−x (0< x

Er-doped oxyfluoride silicate thin films were deposited using pulsed laser deposition. The target glass composition was 65SiO2– 3Al2O3–12Na2O–10PbF3–10LaF3 (in mol%) + 1Er2O3 (in wt.%). Irradiations were performed using an ArF excimer laser in a dynamic flow of oxygen of pressure 5 Pa. The laser fluence at the target surface was 2 J/cm2. Films were deposited on pure silica substrates, either at room temperature or on a substrate-holder heated at 200 °C. The optical transmission of the films in the NIR–visible–UV regions (200–2500 nm) was recorded using a double beam spectrophotometer and was higher than 90%. The optical spectra were analyzed using computer code to evaluate the refraction index (n), the extinction coefficient (k) along with the film thickness. The films deposited at room temperature were cracked whilst examined under scanning electron microscopy and reactive ion etching. By comparison, the films deposited at 200 °C remained undamaged. Optical waveguides were written on the films deposited at 200 °C using dry reactive ion etching with attenuation in the range of 0.74 dB/cm at 633 nm, measured using a prism coupler.

We report on the growth and characterization of gold nitride thin films on Si 〈1 0 0〉 substrates at room temperature by reactive pulsed laser ablation. A pure (99.95%) Au target was ablated with KrF excimer laser pulses in nitrogen containing atmosphere (N 2 or NH 3 ). The gas ambient pressure was varied in the range 0.1–100 Pa. The morphology of the films was studied by using optical, scanning electron and atomic force microscopy, evidencing compact films with RMS roughness in the range 3.6–35.1 nm, depending on the deposition pressure. Rutherford backscattering spectrometry and energy dispersion spectroscopy (EDS) were used to detect the nitrogen concentration into the films. The EDS nitrogen peak does not decrease in intensity after 2 h annealing at 250 °C. Film resistivity was measured using a four-point probe and resulted in the (4–20) × 10 −8 Ω m range, depending on the ambient pressure, to be compared with the value 2.6 × 10 −8 Ω m of a pure gold film. Indentation and scratch measurements gave microhardness values of 2–3 GPa and the Young's modulus close to 100 GPa. X-ray photoemission spectra clearly showed the N 1s peak around 400 eV and displaced with respect to N 2 phase. All these measurements point to the formation of the gold nitride phase.

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.

The intermixing between Mo and Cu under XeCl laser irradiation was studied. The magnetron sputtered Mo Cu multilayers were irradiated at fluences up to 1.4 J cm −2 in vacuum and in nitrogen. Analyses were performed using Rutherford backscattering spectrometry and X-ray diffraction (XRD). The intermixing between Mo and Cu layers as well as SiO 2 underlayer was suppressed by the presence of reactive gases, namely oxygen incorporated into molybdenum. In accordance with the immiscibility of MoCu pair, only Mo and Cu XRD peaks were observed even after laser melting of copper.

We report a study of the characteristics of thin films deposited at room temperature on Si and KBr substrates by XeCl laser ablation of graphite in low pressure (0.25-2.5 mbar) nitrogen and ammonia atmospheres. Very hard films, with a very high electrical resistivity were obtained. The deposition rates decrease with increasing ambient pressure. N/C atomic ratios up to 0.6 were calculated from backscattering measurements. Different diagnostic techniques (XPS, IR absorption spectroscopy, etc.) demonstrate the formation of carbon nitride with a prevalent graphite-like structure. Films deposited in NH3 are thinner and present a lower quantity of N atoms bound to C atoms than films deposited in N2 at the same ambient pressure.

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.

Titanium carbide films were deposited on silicon wafers by XeCl (308 nm) excimer laser ablation of titanium in low pressure (10 −3 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 about 5 J cm −2 . Pulse duration was about 30 ns. The deposited films were characterized by different techniques (X-ray diffraction, scanning electron microscopy and Rutherford backscattering spectrometry).

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.

We deposited CNx films on 〈111〉 Si substrates at room temperature by XeCl laser ablation of graphite targets in low pressure N2 atmosphere at laser fluences in the range of 3 to 16 J/cm2. Different diagnostic techniques (SEM, TEM, RBS, XPS, XRD) were used to characterize the deposited films. Films are plane and adhesive to their substrates. The deposition rates depend on laser fluence, ambient pressure and target to substrate distance. The nitrogen concentration increases with increasing ambient pressure and laser fluence. N/C atomic ratios up to 0.7 were inferred from RBS measurements in films deposited at a fluence of 16 J/cm2. XRD and TEM analyses point to an oriented microcrystalline structure of the films deposited at relatively high laser fluences (12 to 16 J/cm2). This could be due to the high kinetic energy of the radicals in the laser produced plasma plume.

Thin films of Praseodymium-doped chalcogenide glasses [GeS 2 -Ga 2 S 3 -CsI] were prepared by pulsed laser deposition (PLD) technique. The targets were ablated using XeCl (308 nm) and KrF (248 nm) excimer lasers. The films were deposited on microscope glass slides, SiO 2 plates and lithium niobate (LiNbO 3 ) substrates at room temperature and at 300 °C. Morphological, compositional and structural characteristics of deposited films were investigated by different techniques. (Rutherford backscattering spectrometry, scanning electron microscopy and x-ray diffraction). Optical transmission of films and target, at normal incidence, were recorded in the 200-3500 nm spectral region. The optical constants (refractive index n and extinction coefficient k) vs wavelength, as well as the film thickness, were calculated from these spectra with the aid of a computer code. The presence of praseodymium in the doped chalcogenide thin film was analysed by exciting the electrons to the 1 G 4 level and collecting the photoluminescence spectrum in the 1.335 µm region. The waveguiding properties of the deposited films were investigated by the prism coupling technique (m-lines spectroscopy).

A comparison is performed between the relative merits of using an ambient NH 3 atmosphere or a stoichiometrically equivalent N 2 -H 2 (1:3) mixture for the direct laser nitridation of titanium samples by multipulse excimer laser ( λ = 308nm) irradiation. It is shown that the N 2 -H 2 mixture proves more effecient in inhabiting the unwanted interference of the oxidation process and that the whole process proceeds through the action of an erosion plasma on a molten layer covering the laser-irradiated area.

We report a study of the formation of titanium nitride/titanium silicide multistructure layers on silicon single crystals covered with thin (140 and 400 nm) titanium films, by single step multipulse (100 to 5000) XeCl excimer laser irradiation in N 2 atmosphere at a moderate laser fluence (∼ 0.6 J/cm 2 ) and a pulse repetition rate of 50 Hz. After irradiation the samples were submitted to different investigations: optical and electron microscopy, surface resistivity, Rutherford backscattering spectrometry and nuclear reaction analysis. It is shown that the thickness of the silicide and nitride layers can be adjusted by a proper choice of the number of subsequent laser pulses. Optical spectroscopy investigations and temperature profile calculations indicate that titanium nitride is formed at the sample surface through a liquid-phase reaction.

The successful synthesis of silicon nitride directly on the surface of a single‐crystalline silicon wafer by multipulse (up to n=2500) XeCl* excimer (λ=308 nm) laser irradiation in ambient ammonia or nitrogen atmospheres is reported. The amount and quality of the nitrided layers formed are shown to depend on both the number of subsequent laser pulses applied to the same irradiation site as well as on the nature of the ambient gas. Nuclear reactions, Auger electron spectroscopy, Rutherford backscattering spectroscopy, electrical measurements, and optical and electron microscopy were applied to characterize the synthesized surface layers.

We report the surface implantation with boron of Si and Ge by multipulse XeCl excimer ( λ = 308 nm ) or by low-power cw CO 2 ( λ = 10.6 μm ) laser irradiation of Si and Ge wafers covered with a thin (∼ 10 nm ) boron film. In view of minimizing the boron losses by ablation or the boron oxidation in air, the boron deposition on semiconductor wafers was protected with a SiO 2 film when the excimer laser was used. In further experiment we have submitted to pulsed laser irradiation SiO 2 TiB structures deposited on Si and Ge wafers, aiming for both B implantation and the reaction of Ti with the semiconductor at the interface to form a silicide layer. The irradiated samples were examined by optical and electron microscopy and then investigated by RBS and SIMS techniques. Sheet resistance was measured and the p - n characteristics of the formed junctions were recorded. For the first time with pulsed laser processing a p - n junction with boron in germanium was obtained, showing quite good electrical characteristics (breakdown voltage of ∼ 40 V and leakage current of ∼ μA ). Advantageous features and specific limits of the laser technique are discussed.

α-Si 3 N 4 layers have been directly grown on a silicon surface as an effect of excimer (XeCl ∗ ) laser irradiation of silicon wafers in a NH 3 atmosphere. The chemical composition corresponded to a mixture of polycrystalline silicon and pure Si 3 N 4 . By laser irradiation of germanium samples or of silicon samples in N 3 atmosphere, only a thin oxynitride layer with low N concentration is obtained.

Titanium carbide films were deposited on silicon wafers by laser reactive ablation. A pure titanium target placed inside a methane (CH4) atmosphere was irradiated by a XeCl excimer laser with a fluence of 5 J/cm2 and a repetition rate of 8 Hz. Experiments were performed at different values of the ambient pressure in order to investigate the influence of the deposition parameters on the film properties. Results show that at low pressure values (p< 10-5 mbar) the deposited layers are mainly constituted of metallic titanium whereas for pressure ranging from 10-5 to 10-1 mbar they are formed of titanium carbide (TiC) with small amount of oxides. The stoichiometry and thickness of the titanium carbide films can be controlled by the partial pressure of the atmosphere and the number of laser pulses, respectively.

Interdiffusion phenomena, thermal damage and silicide formation in single tungsten-silicon structures and W/Si multilayers under XeCl excimer laser irradiation are studied. Laser fluence ranging from 0.15 to 1.8 J cm−2 were used and up to 300 subsequent laser pulses were directed to the same irradiation site. The samples were examined by X-ray scattering, RBS, TEM and SEM. Only tetragonal WSi2 was formed in our conditions. The lowest resistivity of suicides is 150–300 μΩcm. Si seems to be the predominating diffusing species at the solid W-liquid Si interface.

We report a study of the formation of tungsten silicide at the W-Si interface, induced by multipulse (up to 300 shots) XeCl excimer-laser irradiation of W(150 nm)/Si and W(500 nm)/Si samples. Laser fluences ranging from 0.6 to 1.8 J/cm2 were used. After laser treatment the samples were examined by different diagnostic techniques: Rutherford backscattering spectrometry, X-ray scattering, resistometry, and surface profilometry. Numerical computations of the evolution and depth profiles of the temperature in the samples as a consequence of a single 30 ns laser pulse were performed as well. The results indicate that it is possible to obtain a tungsten silicide layer at the W-Si interface at quite low fluences. The layer thickness increases with the number of laser pulses. Complete reaction of the 150 nm thick W film with silicon was obtained at the fluence of 1.2 J/cm2 between 30 and 100 laser pulses and at 1.5 J/cm2 after 30 laser pulses. The sheet resistance of these silicides was 5–10 Ω. At the used fluences for the 500 nm thick W film only the onset of silicide synthesis at the W-Si interface was observed.

We report on the deposition of thin transition metal nitride (TMN) films by ablating Mo, Ta, V and W targets in low-pressure (1, 10 and 100 Pa) nitrogen atmosphere by KrF excimer laser pulses, and on their characterization. The targets were foils of high purity (99.8%). 3" Si(111) wafers wre used as substrates. Film characteristics (composition, crystalline structure, hardness) were studied as a function of N2 pressure, KrF laser fluence (4.5-19 J/cm2), substrate temperature (20-750°C) and target to substrate distance (30-70 mm). Rutherford backscattering spectrometery (RBS) was used to calculate thickness of the films and identification of the composition. TMN films ar formed already at low N2 ambient pressures (1 Pa) and laser fluences (6 J/cm2) on substrates at room temperature. XRD investigations show that films deposited at elevated temperatures are mostly polycrystalline. While Mo, W and Ta nitrides show respectively a γ-Mo2N, β-W2N and δ-TaN phase in almost any deposition condition, vanadium nitride shows a prevalent phase of δ-VN at N2 pressures of 1-10 Pa, while at higher pressures (100 Pa) and at relatively high laser fluences (16-19 J/cm2) the dominant phase is β-V2N. Generally the crystallinity of the films improves by increasing the substrate temperature. Well-crystallinzed films are obtained on substrates heated at 500°C. Surface morphology, microhardness and electrical resistivity of the films are discussed as a function of both the nitrogen pressure and substrate temperature.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.