Atmospheric Pressure Chemical Vapor Deposition (APCVD) and powder spray pyrolysis are both pyrolytic thin film deposition techniques that are used to coat glass with thin films at atmospheric pressure. In the present study, the fluid dynamics of each process was investigated by laser light scattering. For each system, a 193 nm ArF excimer laser pulsed at 7 Hz was used for the analysis. In the case of the APCVD reactor, the difference in Rayleigh scattering between helium injected in the reactor and ambient air was used to characterize the process. For the powder spray process, laser scattering off the sprayed powder was used. The effect of various parameters is discussed.

The premixability of reagents used in chemical vapor deposition reactors is important to insure that gas feed lines and nozzles do not become clogged with particulates during operation. Even if reactants are to be kept separate until introduced into a reaction chamber, it is desirable to limit the number of particles formed. A reactor which utilizes laser light scattering to monitor particulate formation when gaseous reagents are mixed is described. The reaction of tin (IV) chloride with water is commonly used to produce tin oxide films by chemical vapor deposition. It was found by the light scattering experiment that at temperatures above about 110°C the number of particulates formed is greatly reduced. Therefore, it would be most desirable that these reagents be mixed above this temperature when depositing tin oxide from this reaction. The reaction of titanium tetrachloride with various amine was also investigated by this method. This reaction has been demonstrated to produce titanium nitride above 450°C. For each case, it was observed that there was a temperature above which the number of particulates was significantly reduced. This temperature was always below the optimal temperature for producing titanium nitride films.

The reaction of titanium (IV) chloride and amines in an atmospheric pressure chemical vapor deposition (APCVD) has been previously shown to produce high quality titanium nitride films. These films were gold in appearance with high infrared reflectivity and resistivities as low as 80 microhm-cm. In the present study, the carbon content of the amines was systematically increased and the carbon levels in the films measured by XPS. For primary amines carbon contamination was not detected. Films deposited from secondary and tertiary amines had measurable carbon contamination. Correlation of carbon contamination with electrical resistivity and infrared reflectivity is discussed. Scanning electron micrographs and x-ray diffraction of the films are presented.

Vanadium oxide thin films were grown on glass substrates by atmospheric pressure chemical vapor deposition (APCVD) from the reaction of vanadium(IV) chloride with isopropanol and t-butanol. Films were deposited in the temperature range 250 to 450°C. The as-deposited films were a dark greenish color consistent with formation of a lower oxide of vanadium. Annealing a film deposited on Corning 7059 glass in air converted the material to a yellow film. X-ray diffraction of the yellow film revealed the presence of V2O5. Optical spectra of the films are presented. Glass substrates previously coated with conductive fluorine doped tin oxide were coated with V2O5 and evaluated for electrochromic activity.

Polycrystalline fluorine doped tungsten oxide thin films were deposited onto glass substrates by reacting tungsten hexafluoride, difluoroethane, and isopropanol. The reaction was performed in an atmospheric pressure chemical vapor deposition reactor at a temperature of approximately 400 °C. The electrical conductivity and spectral properties were suggestive of n-type substitutional doping in which oxygen is partially replaced by fluorine. Temperature dependent resistivity measurements were consistent with the presence of polarons. The films were blue in color with enhanced reflectance and absorbance in the IR. These optical characteristics are potentially useful in improving the solar control properties of glass. Scanning electron microscopy revealed a faceted surface morphology. The fluorine atom concentration decreased when the films were annealed in air.