Title page for ETD etd-03122009-040926
|Type of Document
||Hendricks, Warren Charles
||Metallorganic chemical vapor deposition of lead oxide and lead titanate
||Master of Science
||Materials Science and Engineering
|Desu, Seshu B.
|Aning, Alexander O.
|Date of Defense
The purpose of this study was two-fold: firstly, the MOCVD deposition behavior
of Pb(thd)2 was studied in detail and a one-dimensional kinetic model was proposed to
successfully predict the effect of processing conditions on the deposition rate profile for
PbO. Assuming the surface reaction is the rate-limiting step in the process, the effective
activation energy for the process, Ea, was found to be 82 kJ/mol while the
preexponential rate constant was found to be 33 g/cm2/min (0.15 moVcm2/min). The
process was found to consistently produce a combination of the high temperature,
orthorhombic modification of lead monoxide with randomly oriented plates of tetragonal
lead monoxide. TEM electron diffraction was used to investigate the crystal orientation of
the individual plates which was found to be in the plane normal to the <201> zone.
Secondly, the deposition behavior of PbTi03 and the resulting film structure and
properties were investigated. Pb(thd)2 was used in conjunction with titanium ethoxide
(Ti(OEt)4) as a titanium source. Stoichiometric lead titanate films which were found to be
smooth, specular and transparent, and well-adhered were deposited on a variety of
substrates by careful control of the experimental conditions. Film structure, composition,
and thickness were studied and correlated to changes in various experimental parameters.
Additionally, a high temperature regime at which the film stoichiometry is relatively
insensitive to experimental conditions was found to occur. The effects of post-annealing
on the as-deposited films including compositional changes, morphological changes and
crystal structure was also studied. Some problems were obtained with film peeling on the
ruthenium oxide (Ru02)-coated substrates which could be alleviated somewhat by the use
of (100) oriented silicon wafer rather than (111) oriented silicon; a possible mechanism to
explain this behavior is also suggested. Optical properties were obtained using UV -VISNIR
transmission and reflectance spectroscopy; the ferroelectric hysteresis behavior of the
films was observed using standard R T -66 A test equipment.
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