Vapor deposited titanium dioxide thin films - Some properties as a function of crystalline phase

Vapor deposited titanium dioxide thin films - some properties as function of crystalline phas

Preparation of silver-activated zinc sulfide thin films

Silver improves luminescence and reduces contamination of zinc sulfide phosphors. The silver is added after the zinc sulfide phosphors are deposited in thin films by vapor evaporation, but before calcining, by immersion in a solution of silver salt

A study of reactive plasma deposited thin films

A state-of-the-art research laboratory was established to grow and characterize amorphous thin films that are useful in semi-conductor devices. Two film systems, nitride films and silicon dioxide films were studied. Over seventy deposition runs for nitride films were made. The films were deposited on silicon substrate using plasma enhanced chemical vapor deposition. It was found that the uniformity of the films were affected by the location of the film on the platen

Room temperature synthesis of porous SiO2 thin films by plasma enhanced chemical vapor deposition

Synthesis of porous SiO2 thin films in room temperature was carried out using plasma enhanced chemical vapor deposition (CVD) in an electron cyclotron resonance microwave reactor with a downstream configuration.The gas adsorption properties and the type of porosity of the SiO2 thin films were assessed by adsorption isotherms of toluene at room temperature.The method could also permit the tailoring synthesis of thin films when both composition and porosity can be simultaneously and independently controlled. The result shows that it is possible to control the microstructure of oxide thin films deposited by room temperature plasma enhanced chemical vapor depositon (PECVD) by scarificial polymeric organic layers.Ministerio de Ciencia y Tecnología MAT2001-2820European Union ENV4-CT97-063

Thermal Stability of Neodymium Aluminates High- κ

Thin films of neodymium aluminate (NdAlOx) have been deposited by liquid injection metalorganic chemical vapor deposition (MOCVD) using the bimetallic alkoxide precursor [NdAl(OPri)6(PriOH)]2. The effects of high-temperature postdeposition annealing on NdAlOx thin films are reported. The as-deposited thin films are amorphous in nature. X-ray diffraction (XRD) and medium energy ion scattering (MEIS) show, respectively, no crystallization or interdiffusion of metal ions into the substrate after annealing at 950°C. The capacitance-voltage (C-V) and current-voltage (I-V) characteristics of the thin films exhibited good electrical integrity following annealing. The dielectric permittivity (κ) of the annealed NdAlOx was 12, and a density of interface states at flatband (Dit) of 4.01×1011  cm−2 eV−1 was measured. The deposited NdAlOx thin films are shown to be able to endure high-temperature stress and capable of maintaining excellent dielectric properties

In Situ deposition of YBCO high-T(sub c) superconducting thin films by MOCVD and PE-MOCVD

Metalorganic Chemical Vapor Deposition (MOCVD) offers the advantages of a high degree of compositional control, adaptability for large scale production, and the potential for low temperature fabrication. The capability of operating at high oxygen partial pressure is particularly suitable for in situ formation of high temperature superconducting (HTSC) films. Yttrium barium copper oxide (YBCO) thin films having a sharp zero-resistance transition with T( sub c) greater than 90 K and Jc approx. 10 to the 4th power A on YSZ have been prepared, in situ, at a substrate temperature of about 800 C. Moreover, the ability to form oxide films at low temperature is very desirable for device applications of HTSC materials. Such a process would permit the deposition of high quality HTSC films with a smooth surface on a variety of substrates. Highly c-axis oriented, dense, scratch resistant, superconducting YBCO thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 C by a remote microwave-plasma enhanced metalorganic chemical vapor deposition (PE-MOCVD) process. Nitrous oxide was used as a reactant gas to generate active oxidizing species. This process, for the first time, allows the formation of YBCO thin films with the orthorhombic superconducting phase in the as-deposited state. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K with a transition width of about 5 K. MOCVD was carried out in a commercial production scale reactor with the capability of uniform deposition over 100 sq cm per growth run. Preliminary results indicate that PE-MOCVD is a very attractive thin film deposition process for superconducting device technology

The Effect Of Thickness And Interface Interactions On Stability Of Molecular Glasses

Nanometer-scaled thin films of molecular glasses have been widely applied in photovoltaics, organic light emitting diodes, protective coatings and nano-imprint lithography. Studies show that thin films exhibit enhanced overall dynamics, which may affect the stability of thin films produced by physical vapor deposition. Developing a systematic study on the effect of film thickness and the nature of interface interactions (at free surface and film/substrate interface) can therefore help understand how stability of a vapor deposited thin film changes according to its dynamics. In this thesis, I will firstintroduce the construction and operation of an ultra-high vacuum physical vapor deposition setup that allows for a high-throughput preparation of vapor deposited glasses with different substrate temperatures while sharing similar thicknesses. This setup facilitates studies on the structural properties of vapor deposited thin films, such as morphology and anisotropy. The mass density of vapor deposited glasses of various thicknesses, as a measure of their thermodynamic stability, was investigated on thin films of vapor deposited glasses. Results show that the density of vapor deposited glasses formed under certain conditions exceeds the stability of a limiting equilibrium configuration state, i.e. supercooled liquid. The formation of a high-density liquid state has been hypothesized but had not been experimentally identified in the past. I further demonstrated that by altering the supporting substrate interactions of a vapor deposited film to enhance the degree of interactions between the film and the substrate, the degree of stability can be further improved. Preliminary data found that the kinetic stability can also be improved when a weakly interacting substrate is replaced with neutral substrate. These studies may not only inspire new strategies for industrial applications, but also help elucidate the fundamentals of the dependence of glass stability on film dynamics in molecular glass systems