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1.
Thin titanium deuteride (TiDy) films, covered by an ultra-thin palladium layer, have been compared with the corresponding titanium and palladium films using a combination of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The TiDy layers were prepared under ultra-high vacuum (UHV) conditions by precisely controlled deuterium sorption at 298 K on a Ti film evaporated onto a Si(100) substrate. Both Ti and TiDy films were then covered in situ by a nanoscale Pd layer. It was found that a 10- to 12-nm-thick Pd layer protects the TiDy films efficiently against extensive air interaction. The morphology of both the surface and bulk Pd/TiDy (Ti) films have been observed using SEM and cross-sectional TEM analysis, respectively. A polycrystalline bulk morphology in both Ti and TiDy films accompanied by a fine-grained Pd surface was observed. High-magnification cross-sectional TEM images reveal the TiDy film to be plastically deformed leading to an increase in the roughness of the top Pd layer. Complex structures, including Moiré patterns, have been identified within the Pd/TiDy interface. The chemical nature of this interface has been analysed after partial sputtering of the Pd top layer using XPS. Besides TiDy and Pd, TiO and PdO were found to be the main chemical species in the interface region of the Pd/TiHy film. The XPS valence-band spectra of the Pd/TiDy interface reveal electronic features characteristic of a Pd–Ti bimetallic structure.  相似文献   

2.
Using a combination of scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction and X-ray photoelectron spectroscopy (XPS), we made a comparative study of the high-temperature annealing impact on thin titanium deuteride (TiD y ) films covered by an ultrathin Pd layer, and on Ti/Pd bilayer films. The bilayer films were prepared under ultrahigh vacuum conditions and were in situ annealed using the same annealing procedure. It was found that the surface and the bulk morphology of both films undergo different annealing-induced transformations, leading to an extensive intermixing between the Ti and Pd layers and the formation of a new PdTi2 bimetallic phase. Energy-filtered TEM imaging and energy-dispersive X-ray spectrometry analysis, as well as XPS depth profiling all provided evidence of a different distribution of Pd and Ti in the annealed TiD y /Pd film compared with the annealed Ti/Pd film. Our results show that thermal decomposition of TiD y , as a consequence of annealing the TiD y /Pd film, modifies the intermixing process, thereby promoting Ti diffusion into the Pd-rich top layer of the TiD y film and thus providing a more likely path for the formation of the PdTi2 phase than in an annealed Ti/Pd film. Figure Figure Microstructural and chemical characterisation of thin TiDy/Pd film after annealing  相似文献   

3.
The kinetics of thermal evolution of deuterium from ultrathin TiD y /Pd bilayer films has been studied by means of thermal desorption mass spectrometry (TDMS). Using a combination of transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy, we made a study of the complex structural and chemical transformations of the TiD y /Pd film as a result of TDMS-induced evolution of deuterium and simultaneous annealing of this film. Both preparation and TDMS processing of the TiD y /Pd bilayer films were performed in situ under UHV conditions. It was found that the high-temperature TDMS processing of an ultrathin TiD y /Pd film, which was carried out in a relatively short time, leads to a significant film structure transformation. Energy-filtered TEM mapping of cross-section images and EDX analysis revealed extensive interdiffusion of Ti and Pd within the Ti–Pd bi-layer film. This process leads to a progressive change in chemical composition within the surface and subsurface area of the film during the TDMS processing. As the temperature of TDMS heating increases, segregation of Ti at the Pd top layer surface becomes significant. As a result, the kinetics of deuterium desorption is progressively changed during TDMS; at lower temperatures, the kinetics is limited by recombinative processes at the Pd surface, at temperatures beyond 500 K, it becomes dominated by interdiffusion of Ti into the Pd surface.  相似文献   

4.
The interfacial reaction between ultrathin Co film and substrate Si(100) was studied by in situ XPS using monochromatized Al Kα. When the Co is deposited on Si(100) at room temperature, CoSi2 is formed during the initial stage of Co deposition and then metallic Co starts to grow sequentially. For 8 ML Co deposition on Si(100) the interfacial reaction layer is relatively thin compared with the pure Co overlayer, which is not involved in the interfacial reaction in depth. The Co layers change rapidly to CoSi layers after annealing at 270°C, and then CoSi2 layers form after annealing at 540°C for 2 min. The CoSi2 layers are changed to CoSi2 islands by post‐annealing at >650°C. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

5.
Mutual calibration was suggested as a method to determine the absolute thickness of ultrathin oxide films. It was motivated from the large offset values in the reported thicknesses in the Consultative Committee for Amount of Substance (CCQM) pilot study P-38 for the thickness measurement of SiO2 films on Si(100) and Si(111) substrates in 2004. Large offset values from 0.5 to 1.0 nm were reported in the thicknesses by ellipsometry, X-ray reflectometry (XRR), medium-energy ion scattering spectrometry (MEIS), Rutherford backscattering spectroscopy (RBS), nuclear reaction analysis (NRA), and transmission electron microscopy (TEM). However, the offset value for the thicknesses by X-ray photoelectron spectroscopy (XPS) was close to zero (−0.013 nm). From these results, the mutual calibration method was reported for the thickness measurement of SiO2 films on Si(100) by combination of TEM and XPS. The mutual calibration method has been applied for the thickness measurements of hetero oxide films such as Al2O3 and HfO2. Recently, the effect of surface contamination was reported to be critical to the thickness measurement of HfO2 films by XPS. On the other hand, MEIS was proved to be a powerful zero offset method which is not affected by the surface contamination. As a result, the reference thicknesses in the CCQM pilot study P-190 for the thickness measurement of HfO2 films on Si(100) substrate were determined by mutual calibration method from the average XRR data and MEIS analysis. Conclusively, the thicknesses of ultrathin oxide films can be traceably certified by mutual calibration method and most thickness measurement methods can be calibrated from the certified thicknesses.  相似文献   

6.
Five polyimide films prepared from 3,3′,4,4′-benzophenone tetracarboxylic acid'dianhydride (BTDA) and diamines, 4,4′-oxydianiline (ODA), 3,3′-diaminobenzophenone (DABP), or 3,3′-diaminodiphenylcarbinol (DADPC) and doped with Li2PdCl4 (LTP) or Pd[(CH3)2S]2Cl2 (PDS) were selected for a detailed x-ray photoelectron spectroscopic (XPS) study to determine the oxidation state of palladium and the relative distribution of this and other elements in these films, especially as they relate to electrical resistivity. XPS shows that Pd in the films is present as a mixture of zero and +2 valence states. Films that contain lithium as part of the dopant all show that metal is present as Li+ and Li2O, a fact that may have a bearing on film electrical properties. An Auger electron spectroscopic (AES) or XPS profiling was performed on two of the electrically conductive films. A film doped with PDS reveals a majority of palladium at the surface as Pd(0) and much smaller amounts in film bulk as a mixture of Pd(0) and Pd(II). Film behavior is similar to a metal-vapor deposited film. An LTP doped film, by contrast, exhibits a homogeneous composition with a mixture of Pd(0) and Pd(II). These studies support others that use chemical etching on the film surfaces. Scanning electron microscopy (SEM) has been used to provide surface evaluations.  相似文献   

7.
Lead zirconate titanate (PZT) thin films were deposited on Pt/Ti/SiO2/Si and interlayer/Pt/Ti/SiO2/Si substrate by radio frequency (r.f.) magnetron sputtering with a Pb1.1Zr0.53Ti0.47O3 target. The crystallization of the PZT thin films was formed only by substrate temperature. When interlayer (PbO/TiO2) was inserted between the PZT thin film and the Pt electrode, the grain growth and processing temperature of the PZT thin films were considerably improved. Compared to PZT/Pt structure, the dielectric constant and polarization properties of the PZT/interlayer/Pt structure were fairly improved. In particular, PZT/interlayer/Pt at the substrate temperature of 400 °C showed prevalent ferroelectric properties (r=475.97, tanδ=0.0591, Pr=23 μC/cm2). As a result of an X-ray photoelectron spectroscopy (XPS) depth-profile analysis, it was found that PZT/interlayer/Pt deposited only by substrate temperature without the post-annealing process via r.f. magnetron sputtering method remained independent of each other regardless of substrate temperatures.  相似文献   

8.
Fabrication of ferroelectric Pb(Zr0.52Ti0.48)O3 (PZT) thick films on a Pt/Ti/SiO2/Si substrate using powder-mixing sol-gel spin coating and continuous wave CO2 laser annealing technique to treat the specimens with at a relatively low temperature was investigated in the present work. PZT fine powders were prepared by drying and pyrolysis of sol-gel solutions and calcined at temperatures from 400 to 750°C. After fine powder-containing sol-gel solutions were spin-coated on a substrate and pyrolyzed, CO2 laser annealing was carried out to heat treat the specimens. The results show that laser annealing provides an extremely efficient way to crystallize the materials, but an amorphous phase may also form in the case of overheating. Thicker films absorb laser energy more effectively and therefore melt at shorter periods, implying a significant volume effect. A film with thickness of 1 μm shows cracks and rough surface morphology and it was difficult to obtain acceptable electrical properties, indicating importance of controlling interfacial stress and choosing appropriate size of the mixing powders. On the other hand, a thick film of 5 μm annealed at 100 W/cm2 for 15 s exhibits excellent properties (P r = 36.1 μC/cm2, E c = 19.66 kV/cm). Films of 10 μm form a melting zone at the surface and a non-crystallized bottom layer easily at an energy density of 100 W/cm2, showing poor electrical properties. Besides, porosity and electrical properties of thick films can be controlled using appropriate processing parameters, suggesting that CO2 laser annealing of modified sol-gel films is suitable for fabricating films of low dielectric constants and high crystallinity.  相似文献   

9.
Copper sulphide CuS was deposited on three substrates; glass, Indium Tin Oxide (ITO) and Ti by using spray pyrolysis deposition (SPD). After depositing CuS thin films on the substrates at 200 °C, they were annealed at 50, 100, 150, and 200 °C for 1 hour. Structural measurements revealed covellite CuS and chalcocite Cu2S phases for thin films before and after annealing at 200 °C with changes in intensities, and only covellite CuS phase for thin films after annealing at 50, 100, and 150 °C. Morphological characteristics show hexagonal-cubic crystals for the CuS thin film deposited on glass substrate and plates structures for films deposited on ITO and Ti substrates before annealing, these crystals became bigger in size and there were be oxidation and some agglomerations in some regions with formation of plates for CuS on glass substrate after annealing at 200 °C. For Hall Effect measurements, thin films sheet resistivity and mobility increased after annealing while the carrier concentration decreased. Generally, the thin film deposited on ITO substrate had the lowest resistivity and the highest carrier concentration before and after annealing. The thin film deposited on Ti substrate had the highest mobility before and after annealing, which makes it the best thin film for device performance. The objective of this research is to show the improvement of thin films electrical properties especially the mobility after annealing those thin films.  相似文献   

10.
The possibility of forming niobium oxynitride through the nitridation of niobium oxide films in molecular nitrogen by rapid thermal processing (RTP) was investigated. Niobium films 200 and 500 nm thick were deposited via sputtering onto Si(100) wafers covered with a thermally grown SiO2 layer 100 nm thick. These as-deposited films exhibited distinct texture effects. They were processed in two steps using an RTP system. The as-deposited niobium films were first oxidized under an oxygen atmosphere at 450 °C for various periods of time and subsequently nitridated under a nitrogen atmosphere at temperatures ranging from 600 to 1000 °C for 1 min. Investigations of the oxidized films showed that samples where the start of niobium pentoxide formation was detected at the surface and the film bulk still consisted of a substoichiometric NbOx phase exhibited distinctly lower surface roughness and microcrack densities than samples where complete oxidation of the film to Nb2O5 had occurred. The niobium oxide phases formed at the Nb/substrate interface also showed distinct texture. Zones of niobium oxide phases like NbO and NbO2, which did not exist in the initial oxidized films, were formed during the nitridation. This is attributed to a “snow-plough effect” produced by the diffusion of nitrogen into the film, which pushes the oxygen deeper into the film bulk. These oxide phases, in particular the NbO2 zone, act as barriers to the in-diffusion of nitrogen and also inhibit the outdiffusion of oxygen from the SiO2 substrate layer. Nitridation of the partially oxidized niobium films in molecular nitrogen leads to the formation of various niobium oxide and nitride phases, but no indication of niobium oxynitride formation was found. Figure Schematic representation of the phase distribution in 200 nm Nb film on SiO2/Si substrate after two steps annealing using an RTP system. The plot below represents the SIMS depth profiles of the nitridated sample with the phase assignment  相似文献   

11.
The XPS (X-ray photoelectron spectroscopy) study of nickel oxide nanolayers obtained by magnetron sputtering of the metal and its subsequent oxidation in air at different temperatures (400°C and 1000°C) was performed. Silicon(100) was used as a substrate. Surface of the initial Ni/Si structure was shown to contain not only Ni metal, but also the NiO oxide. Annealing at 400°C results in a complete oxidation of the metal film. At a high-temperature annealing (1000°C), nickel interacts both with oxygen and silicon substrate to form NiSi silicide and a composite Ni-Si-O phase in transition layer. Electronconductivity of NiO films is determined by intercrystallite barriers. Activation energies of film electroconductivity in model gases (O2, Ar, H2) were found.  相似文献   

12.
Thin films of cobalt (10, 40, and 100 nm) are deposited on Si substrate by electron beam physical vapor deposition technique. After deposition, 4 pieces from each of the wafers of silicon substrate were cut and annealed at a temperature of 200°C, 300°C, and 400°C for 2 hours each, separately. X‐ray diffraction, atomic force microscopy, and transmission electron microscopy (TEM) are used to study the structural and morphological characteristics of the deposited films. To obtain TEM images, Co films are deposited on Cu grids; so far, no such types of TEM images of Co films are reported. Structural studies confirm nanocrystalline nature with hexagonal close packed structure of the deposited Co film at lower thickness, while at higher thickness, film structure transforms to amorphous with lower surface roughness value. The particle sizes in all the cases are in the range of 3 to 5 nm. Micro‐Raman spectroscopy is also used to study the phase formation and chemical composition as a function of thickness and temperature. The results confirm that the grown films are of good quality and free from any impurity. Studies show the silicide formation at the interface during deposition. The appearance of new band at 1550 cm−1 as a result of annealing indicates the structural transformation from CoSi to CoSi2, which further enhances at higher annealing temperatures.  相似文献   

13.
ZnO thin films were successfully deposited on SiO2/Si substrate using the sol–gel technique and annealed in various annealing atmospheres at 900 °C by rapid thermal annealing (RTA). X-ray diffraction revealed the (002) texture of ZnO thin films. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that the grains of the ZnO thin film were enlarged and its surface was smoothed upon annealing in oxygen. PL measurement revealed two ultraviolet (UV) luminescence bands at 375 and 380 nm. The intensity of the emission peak at 380 nm became stronger as the concentration of oxygen in the annealing atmosphere increased. The X-ray photoelectron spectrum (XPS) demonstrated that a more stoichiometric ZnO thin film was obtained upon annealing in oxygen and more excitons were generated from the radiative recombination carriers consistently. Additionally, the UV intensity increased with the thickness of ZnO thin film.  相似文献   

14.
Ag x Cd y S nanoparticles were obtained in arachidic acid (AA) monolayer containing Ag+ and Cd2+ under H2S flow. The AA/Ag x Cd y S monolayers were deposited onto solid substrate to prepare LB films. The UV-vis spectrum showed that the LB film exhibited notable quantum-size effect. The small-angle X-ray diffraction revealed periodic structure of the LB films. The molar ratio of Ag to Cd in AA/Ag x Cd y S film was ca. 1 : 5 as measured by the XPS. TEM and FTIR spectroscopy showed that the head-groups of arachidic acid molecules controlled formation of Ag x Cd y S nanoparticles in the monolayer.  相似文献   

15.
PdCuAu ternary alloy samples with different composition were synthesized on top of ZrO2‐modified porous stainless steel disks by the sequential electroless deposition technique. The structure, morphology and bulk composition of the samples were characterized by X‐ray diffraction (XRD), scanning electron microscopy and energy dispersive X‐ray spectroscopy (EDX). Complete alloy formation with a pure fcc phase for the Pd71Cu26Au3, Pd70Cu25Au5 and Pd67Cu24Au9 samples and a bcc structure for the Pd62Cu36Au2 and Pd60Cu37Au3 samples were obtained upon annealing at 500 °C for 120 h as revealed by XRD. A combination of low‐energy ion scattering (LEIS) and X‐ray photoelectron spectroscopy (XPS) was used to investigate the surface properties of the PdCuAu alloys. XPS results confirmed alloy formation under the annealing conditions. XPS analysis also revealed that the near‐surface regions of the alloys became enriched in Pd with respect to the bulk composition determined by EDX. In contrast, LEIS and angle‐resolved XPS analyses showed that the top‐most surface layers in all samples were copper‐rich compared with the bulk composition. This high Cu surface concentration could impart resistance to bulk sulfide formation to the PdCuAu alloy membranes. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

16.
Growth of magnetron sputtered Pt/CeO2 thin films on Si and Si3N4 were characterized by X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and X‐ray photoelectron spectroscopy (XPS). Interaction of Pt/CeO2 films with Si on Si and Si3N4 substrates was extensively investigated by XPS. XRD studies show that films are oriented preferentially to (200) direction of CeO2. XPS results show that Pt is mainly present in +2 oxidation state in Pt/CeO2/Si film, whereas Pt4+ predominates in Pt/CeO2/Si3N4 film. Concentration of Pt4+ species is more than four times on Si3N4 substrate as compared with that on Si. Ce is present as both +4 and +3 oxidation states in Pt/CeO2 films deposited on Si and Si3N4 substrates, but concentration of Ce3+ species is more in Pt/CeO2/Si film. Interfacial reaction between CeO2 and Si substrate is controlled in the presence of Pt. Pt/Ce concentration ratio decreases in Pt/CeO2/Si3N4 film upon successive sputtering, whereas this ratio decreases initially and then increases in Pt/CeO2/Si film. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

17.
The suitability of PVD films of γ-Al2O3 and of ternary Al-O-N as diffusion barriers between a nickel based superalloy CMSX-4 and NiCoCrAlY for a possible application in gas turbines was investigated. Therefore, an Al2O3 film and, alternatively, an Al-O-N film were deposited on CMSX-4 at 100 °C substrate temperature by means of reactive magnetron sputtering ion plating (MSIP). After characterization of composition and structure of the films by X-ray photoelectron spectroscopy (XPS) and grazing incidence X-ray diffraction (XRD), a NiCoCrAlY coating was deposited onto the diffusion barriers and, for comparison, directly onto CMSX-4 by MSIP as well. The composites were annealed for 4 h at 1100 °C under inert atmosphere. Wavelength dispersive X-ray (WDX) element mappings and line-scans of the cross-sectional cut served to evaluate the suitability of the films as diffusion barriers. After detachment of the coatings from the substrate, the phase stabilities of the two metastable phases γ-Al2O3 and Al-O-N were determined by means of grazing incidence XRD. Without a diffusion barrier, enhanced interdiffusion was observed. Analyses of the composite with the γ-Al2O3 interlayer revealed diffusion of Ti and Ta from the substrate into the NiCoCrAlY coating. No interdiffusion of Ni, Ti, Ta, and Cr could be detected in case of the ternary Al-O-N film. Whereas the ternary Al-O-N film remained in the as-deposited X-ray amorphous structure after annealing, a phase change from the γ to the α modification could be observed in case of the Al2O3 film, presumably responsible for its lower efficiency as a diffusion barrier. Received: 19 September 1998 / Revised: 14 April 1999 / Accepted: 18 April 1999  相似文献   

18.
In this paper Al, Zn and Al–43.4Zn–1.6Si (AlZn) alloy‐coated steel have been treated with the organofunctional silane γ‐mercaptopropyltrimethoxysilane (γ‐MPS) and the non‐organofunctional silane 1,2‐bis(triethoxysilyl)ethane (BTSE). Also, a two‐step treatment of metal substrates was performed: the metal substrates were treated with the BTSE silane followed by a γ‐MPS treatment. The influence of metal substrate and the pH value of the silane film properties were investigated using time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS). The results show that the BTSE silane is fully hydrolysed but the γ‐MPS silane is not. The presence of negative ions of the type HSixOy? indicates that both types of silane films are highly cross‐linked via Si–O–Si bonds. The two‐step treatment gave a γ‐MPS silane layer on top of the BTSE silane layer but the thickness of the total silane film become thinner than for a single BTSE film, indicating that some of the BTSE is dissolved during the γ‐MPS deposition step. Furthermore, the ToF‐SIMS results show that the thiol group of the γ‐MPS silane is oxidized. Finally, no major influence, either in the positive or the negative mass spectra, from the different metal substrates could be detected for the silane films investigated. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

19.
Amorphous carbon silicon nitride thin films were grown on (100) oriented silicon substrates by pulsed laser deposition (PLD) assisted by an RF nitrogen plasma source. Up to about 30 at. % nitrogen and up to 20 at. % silicon were found in the hard amorphous thin films by XPS in dependence on the composition of the mixed graphite / Si3N4 PLD target. The universal nanohardness was measured to be at maximum load force of 0.1 mN up to 23 GPa for thin CSixNy films with reference value of 14 GPa for single crystalline silicon. X-ray photoelectron spectroscopy (XPS) of CSixNy film surfaces showed a clear correlation of binding energy and intensity of fitted features of N 1s, C 1s, and Si 2p peaks to the composition of the graphite / Si3N4 target and to nitrogen flow through the plasma source, indicating soft changes of binding structure of the thin films due to variation of PLD parameters. Auger electron spectroscopy (AES) of Si KL23L23;1D Auger transition gave a detailed view of bonding structure of Si in the CSixNy films. The intensity of π* and σ* resonances at the carbon K-edge X-ray absorption near-edge structure (XANES) of the CSixNy films measured at BESSY I corresponded to the nanohardness of the CSixNy films, thus giving insight into chemical binding structure of superhard amorphous materials.  相似文献   

20.
Mono- and multilayer HfO2 sol–gel thin films have been deposited on silicon wafers by dip-coating technique using a solution based on hafnium ethoxide as precursor. The densification/crystallization process was achieved by classical annealing between 400 and 600 °C for 0.5 h (after drying at 100 °C). Systematic TEM studies were performed to observe the evolution of the thin film structure depending on the annealing temperature. The overall density of the films was determined from RBS spectrometry correlated with cross section (XTEM) thickness measurements. After annealing at 450 °C the films are amorphous with a nanoporous structure showing also some incipient crystallization. After annealing at 550 °C the films are totally crystallized. The HfO2 grains grow in colonies having the same crystalline orientation with respect to the film plane, including faceted nanopores. During annealing a nanometric SiO2 layer is formed at the interface with the silicon substrate; the thickness of this layer increases with the annealing temperature. Capacitive measurements allowed determining the value of the dielectric constant as 25 for four layer films, i.e. very close to the value for the bulk material.  相似文献   

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