Metal alkoxides have been known for many years. Recently, a renewed interest in
these compounds has arisen as they have been found to be viable precursors for metal
oxide film synthesis. Lead zirconium titanate(PZT) films have shown promise for many
applications in the electronics industry. Chemical vapor deposition(CVD) of PZT thin
films has been hampered by the lack of a suitable zirconium precursor for low
temperature chemical vapor deposition. Currently, both zircbnium alkoxides and
zirconium β-diketonate complexes are employed in the CVD process of PZT films. The
alkoxides, although volatile are moisture sensitive and are not easily handled under
normal atmospheric conditions. Tetrakis β-diketonate complexes of zirconium are more
stable than the alkoxides, but they have a deposition temperature that is too high for
commercial use. A mixed β-diketonate zirconium alkoxide compound could provide the
necessary stability while maintaining the volatility necessary for low temperature CVD.
From the above reasoning, it was decided to prepare a zirconium di-(2,2,6,6
tetramethyl-3,5 heptadione) di-tert-butoxide compound. The compound was
characterized and subjected to a variety of volatility studies. Thermogravimetric analysis
provided evidence that the compound was volatile enough to be used in thin film
synthesis. Initial attempts at film deposition, however, resulted in no film growth.
Changing deposition parameters also resulted in no film growth. Visual inspection of the
residue left after the deposition trials gave the first indication that the compound had
undergone some change. Analysis of the material left in the reactor suggested the
formation of a zirconium cluster compound. Further decomposition studies also resulted
in the formation of the same zirconium cluster compound.
Attempts to make the compound more stable at deposition temperatures centered
on changing the alkoxide. Tri-tert-butyl alcohol(tritox) was prepared, however, the
synthesis of the tritox - β-diketonate zirconium complex was unsuccessful. Other
changes involved using pivalic acid to replace the alkoxide. Reactions with pivalic acid
and zirconium di-(2,2,6,6 tetramethyl-3,5 heptadione) di-tert-butoxide resulted in the
decomposition of the starting material.
Other β-diketonate complexes were also investigated. Compounds synthesized
from 2.4 pentadione(Acac), I-benzoyl acetone(Bzac) and dibenzoyl methane(Dbzm)
could not be purified in order to subject them to chemical vapor deposition.
A zirconium complex with two different β diketonate ligands was also
synthesized. The complex was not investigated as a precursor for chemical vapor
deposition because the isomers of the complex could not be separated.
next to an author's name indicates that all files or directories associated with their ETD are accessible from the Virginia Tech campus network only.
![[VT]](http://scholar.lib.vt.edu/images/ETD-db/restricted.gif)
