A single-source precursor to titanium nitride thin films. Evidence for the intermediacy of imido complexes in the chemical vapor deposition process
- Wayne State Univ., Detroit, MI (United States); and others
Monomeric titanium and zirconium complexes with multiple bonds to oxygen, sulfur, and nitrogen have attracted considerable attention due to their novel structural features and interesting reactivity. Recently, we have initiated a research program that is designed to prepare models for complexes involved in chemical vapor deposition (CVD) processes of early transition metal materials. Species containing metal-element multiple bonds have featured prominently in mechanistic conjecture about CVD reactions, although little hard evidence is available to back up such speculation. It was disclosed that excellent-quality thin films of titanium nitride can be prepared by the atmospheric pressure CVD reaction of titanium tetrachloride with alkylamines at temperatures between 350 and 600 {degrees}C. This process appeared ideal for detailed mechanistic scrutiny, since titanium tetrachloride is well-known to be highly reactive toward amines{sup 9} and because titanium should be capable of stabilizing a variety of nitrogen ligand types. In this context, we report the synthesis and characterization of two complexes that are formed in the solution-phase reactions of titanium tetrachloride with tert-butylamine. To the best of our knowledge, the first of these, a chloride-amide-amine complex, comprises the first single-source CVD precursor to high-quality gold-colored films of titanium nitride. Additionally, a monomeric imido complex has been trapped with triphenyl-phosphine oxide and has been structurally characterized. Evidence is presented from mass spectrometry for the intermediacy of imido complexes in the CVD process. The present results provide partial mechanistic insight into the sequence that leads from titanium tetrachloride and tert-butyl-amine to titanium nitride thin films. The system implies that imido complexes play an important role in other film forming processes.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 171652
- Journal Information:
- Journal of the American Chemical Society, Vol. 114, Issue 3; Other Information: PBD: 29 Jan 1992
- Country of Publication:
- United States
- Language:
- English
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