Tetrakis(dimethylamino)titanium (TDMAT) is a
chemical compound. The compound is generally classified as a
metalorganic species, meaning that its properties are strongly influenced by the organic ligands but the compound lacks metal-carbon bonds. It is used in
chemical vapor deposition
Chemical vapor deposition (CVD) is a vacuum deposition method used to produce high quality, and high-performance, solid materials. The process is often used in the semiconductor industry to produce thin films.
In typical CVD, the wafer (substra ...
to prepare
titanium nitride (TiN) surfaces and in
atomic layer deposition
Atomic layer deposition (ALD) is a thin-film deposition technique based on the sequential use of a gas-phase chemical process; it is a subclass of chemical vapour deposition. The majority of ALD reactions use two chemicals called precursors (also ...
as a
titanium dioxide precursor. The prefix "tetrakis" refers the presence of four of the same
ligand, in this case dimethylamides.
Preparation and properties
Tetrakis(dimethylamino)titanium is a conventional Ti(IV) compound in the sense that it is tetrahedral and diamagnetic. Unlike the many
alkoxide
In chemistry, an alkoxide is the conjugate base of an alcohol and therefore consists of an organic group bonded to a negatively charged oxygen atom. They are written as , where R is the organic substituent. Alkoxides are strong bases and, whe ...
s, the diorganoamides of titanium are monomeric and thus at least somewhat volatile. It is prepared from
titanium tetrachloride (which is also tetrahedral, diamagnetic, and volatile) by treatment with lithium dimethylamide:
[D. C. Bradley and I. M. Thomas, "Part I. Metallo-organic Compounds containing Metal-Nitrogen bonds. Some Dialkylamino-derivatives of Titanium and Zirconium" J. Chem. Soc. 1960, 3857-3861. .]
:TiCl
4 + 4 LiNMe
2 → Ti(NMe
2)
4 + 4 LiCl
Like many amido complexes, TDMAT is quite sensitive toward water, and its handling requires
air-free techniques. The ultimate products of its
hydrolysis is
titanium dioxide and
dimethylamine:
:Ti(NMe
2)
4 + 2 H
2O → TiO
2 + 4 HNMe
2
In a related reaction, the compound undergoes exchange with other amines, evolving
dimethylamine.
See also
*
Metalorganic chemical vapor deposition (MOCVD), general process which includes using TDMAT but also uses many other gases to layer other substances.
References
Semiconductor device fabrication
Titanium(IV) compounds
Metal amides
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