Study on Ti-SiO2 Reaction - Thermodynamic Approach

1995 ◽  
Vol 402 ◽  
Author(s):  
M. B. A. Fontes ◽  
J. D. T. Capocchi ◽  
J. C. Acquadro

AbstractInteractions between Ti and SiO2 thin films have been studied in self-aligned transistor process in the MOS Integrated Circuits Technology. A thermodynamic study of this interaction was conducted on the titanium and silicon dioxide chemistry. The Gibbs free energy was analyzed in the 25 to 1000°C range and it was concluded that the 11/3 Ti + SiO2 --> 1/3 Ti5 Si3 + 2 Ti reaction has the lowest free energy. Ti thin films were deposited by sputtering over dry silicon oxide and then sintered in atmospheric pressure furnace - RTP at argon ambient. The samples were analyzed by X-RAY Diffraction (XRD), Rutherford Backscatering Spectroscopy (RBS) and fourpoint- probe resistivity measurements. It was showed that experimental results can be modeled by theoretical analysis.

2007 ◽  
Vol 1040 ◽  
Author(s):  
Hiroki Iwane ◽  
Naoki Wakiya ◽  
Naonori Sakamoto ◽  
Takato Nakamura ◽  
Hisao Suzuki

AbstractEpitaxial aluminum nitride (AlN) thin films were successfully prepared on the (0001) sapphire substrate by chemical vapor deposition (CVD) using aluminum iodide (AlI3) and ammonia (NH3) under atmospheric pressure at 750 ºC. The crystallographic relationship between AlN thin films and Al2O3 substrate is in the following; AlN(0001)//Al2O3(0001) and AlN[1010]//Al2O3[1120]. Lattice parameters of AlN thin film measured by X-ray diffraction revealed that c=0.498 and a=0.311 nm, respectively. Residual stress estimated by modified sin2ψ method was 0.38 GPa in compressive stress. Cross-sectional TEM observation revealed that an interlayer lies between the AlN films and the sapphire substrate. It was suggested that relaxation of residual stress caused by the mismatching of lattice parameter and thermal expansion coefficient was brought about by the interlayer.


2004 ◽  
Vol 848 ◽  
Author(s):  
Oren Metz ◽  
Joshua Pelleg ◽  
Misha Sinder ◽  
Roni Shneck ◽  
Vladimir Sokolovsky

ABSTRACTThe discovery of the new superconductor MgB2 with critical temperature of Tc = 39 K stimulated great activity in search for materials with higher Tc. Theoretical works predicted the possibility of obtaining such superconducting materials in other borides also, in particular in AgB2. It was predicted in these works that diborides of metals having the AlB2 type structure, among them AgB2 may have superconductivity with a Tc higher than 39 K. In an early very short report the lattice parameters of AgB2 were evaluated in a synthesized specimen. However, no other indication exists that AgB2 was ever produced. We report the preliminary results of our attempts to prepare AgB2 films.Thin films of Ag-B were produced by magnetron cosputtering in Ar ambient from two separate targets that of B and Ag on Si (100) substrates. The specimens were subjected to X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photo spectroscopy (XPS), Auger analysis and optical microscope (OM) investigations. Resistivity measurements in a wide temperature range were measured. No superconductivity was yet observed in the range ∼10 – 200. K on the basis of resistivity measurements. Preliminary results indicate that AgB2 might be an unstable phase.


1986 ◽  
Vol 77 ◽  
Author(s):  
O. F. De Lima ◽  
Y. Lepetre ◽  
M. B. Brodsky

ABSTRACTTEM, X-ray diffraction, and electrical resistivity measurements were used to study the microstructure and the growth of AI-Cr-AI film sandwiches, where the individual Al layers were 300 Å thick and the Cr thickness was varied between 0–10 atomic layers. The base vacuum was around 1.0 × 10−10 torr, substrate temperatures varied between 100–350 °C, and evaporation rates were 3Å/s for Al and ∼0.1 – 0.2 Å/s for Cr. All Al films had a strong (111) texture and showed a non-percolative island structure at 350 °C. The films became connected at lower substrate temperatures, reaching perfect continuity at 100°C. However, electrical conductivity is achieved also for the films deposited at 350 °C when one or more atomic layers of Cr are sandwiched between the Al layers. Results for the superconducting critical temperature and resistivity are discussed in terms of Cr diffusion into Al and the film size effect.


1990 ◽  
Vol 5 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Masanori Nemoto ◽  
Mitsugu Yamanaka

Superconducting Bi-Sr-Ca-Cu-O thin films have been prepared for the first time by chemical vapor deposition using triphenyl bismuth and fluorocarbon-based chelates such as bis(hexafluoroacetylacetonate)strontium, bis(hexafluoroacetylacetonate)calcium, and bis(hexafluoroacetylacetonate)copper. After annealing in air, x-ray diffraction data reveal that the films deposited on (001) SrTiO3 substrates have preferential orientation of their crystalline c-axis perpendicular to the substrate surface. Four-probe resistivity measurements reveal the onset of superconductivity at 80 K and zero resistivity at 50 K.


2007 ◽  
Vol 26-28 ◽  
pp. 593-596 ◽  
Author(s):  
You Zhen Li ◽  
Ji Cheng Zhou

Ta-Al-N thin films on Si wafer were prepared by RF reactive magnetron sputtering in a N2/Ar ambient. Then the stacked structures of Cu/Ta-Al-N/Si were prepared and annealed at temperatures varied from 400°C to 900°C for 5 minutes in a N2 ambient tube. Four-point probe (FPP) sheet resistance measurement, Atomic force microscope (AFM), Scanning electron microscope(SEM), Alpha-Step IQ Profilers and X-ray Diffraction(XRD) were used to investigate the composition, morphology and the diffusion barrier properties of the thin films. The results show that with the increasing of Al component, the surface of Ta-Al-N thin-films became finer, the sheet resistance became higher, and after annealing at 800°C/300S FA, Cu diffusion through Ta-Al-N barrier didn’t not occurred. Results show that Ta-Al-N thin-films could act as diffusion barrier for new generation integrated circuits due to its excellent high temperature properties.


Author(s):  
F. Ma ◽  
S. Vivekanand ◽  
K. Barmak ◽  
C. Michaelsen

Solid state reactions in sputter-deposited Nb/Al multilayer thin films have been studied by transmission and analytical electron microscopy (TEM/AEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The Nb/Al multilayer thin films for TEM studies were sputter-deposited on (1102)sapphire substrates. The periodicity of the films is in the range 10-500 nm. The overall composition of the films are 1/3, 2/1, and 3/1 Nb/Al, corresponding to the stoichiometric composition of the three intermetallic phases in this system.Figure 1 is a TEM micrograph of an as-deposited film with periodicity A = dA1 + dNb = 72 nm, where d's are layer thicknesses. The polycrystalline nature of the Al and Nb layers with their columnar grain structure is evident in the figure. Both Nb and Al layers exhibit crystallographic texture, with the electron diffraction pattern for this film showing stronger diffraction spots in the direction normal to the multilayer. The X-ray diffraction patterns of all films are dominated by the Al(l 11) and Nb(l 10) peaks and show a merging of these two peaks with decreasing periodicity.


2003 ◽  
Vol 775 ◽  
Author(s):  
Donghai Wang ◽  
David T. Johnson ◽  
Byron F. McCaughey ◽  
J. Eric Hampsey ◽  
Jibao He ◽  
...  

AbstractPalladium nanowires have been electrodeposited into mesoporous silica thin film templates. Palladium continually grows and fills silica mesopores starting from a bottom conductive substrate, providing a ready and efficient route to fabricate a macroscopic palladium nanowire thin films for potentially use in fuel cells, electrodes, sensors, and other applications. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicate it is possible to create different nanowire morphology such as bundles and swirling mesostructure based on the template pore structure.


2016 ◽  
Vol 12 (3) ◽  
pp. 4394-4399
Author(s):  
Sura Ali Noaman ◽  
Rashid Owaid Kadhim ◽  
Saleem Azara Hussain

Tin Oxide and Indium doped Tin Oxide (SnO2:In) thin films were deposited on glass and Silicon  substrates  by  thermal evaporation technique.  X-ray diffraction pattern of  pure SnO2 and SnO2:In thin films annealed at 650oC and the results showed  that the structure have tetragonal phase with preferred orientation in (110) plane. AFM studies showed an inhibition of grain growth with increase in indium concentration. SEM studies of pure  SnO2 and  Indium doped tin oxide (SnO2:In) ) thin films showed that the films with regular distribution of particles and they have spherical shape.  Optical properties such as  Transmission , optical band-gap have been measured and calculated.


2019 ◽  
Vol 15 (34) ◽  
pp. 1-14
Author(s):  
Bushra A. Hasan

Lead selenide PbSe thin films of different thicknesses (300, 500, and 700 nm) were deposited under vacuum using thermal evaporation method on glass substrates. X-ray diffraction measurements showed that increasing of thickness lead to well crystallize the prepared samples, such that the crystallite size increases while the dislocation density decreases with thickness increasing. A.C conductivity, dielectric constants, and loss tangent are studied as function to thickness, frequency (10kHz-10MHz) and temperatures (293K-493K). The conductivity measurements confirm confirmed that hopping is the mechanism responsible for the conduction process. Increasing of thickness decreases the thermal activation energy estimated from Arhinus equation is found to decrease with thickness increasing. The increase of thickness lead to reduce the polarizability α while the increasing of temperature lead to increase α.


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