Ferroelectric and other high dielectric constant metal oxides currently are sought-after for a variety of applications in the electronics industry. To meet the demand of preparation of these interesting materials in a manner comnpatible with traditional silicon-based fabrication procedures, chemical vapor deposition routes are desired for film growth. Compounds displaying high vapor phase stability are necessary as precursors for these apprlications. Additionally, in general, it is preferred to utilize compounds in a liquid state, due to the more rapid re-establishment of equilibrium at a liquid-vapor interface, compared to that present at a solid-vapor intefface. This combination of desired molecular properties, in turn, presents a great challenge to the coordination chemist. Several of the metals of interest for these uses reside in groups 2-5. Common design features are emerging for the ligands best suited for attachment to these metals for saturation of the relatively high ionic radii exhibited by most of these elements, multidentate, monoanionic ligands are relied upon. In the past, most often, homoleptic ligand sets ahve been employed, thereby reducing the chance for ligand scramblind to occur during the growth process. Such disproportionation processes have been credited, in previous work, with the observation of a temperal decay in vapor pressure of heteroleptic compounds. In some interesting new developments, it has been found that heteroleptic compounds possess sufficient vapor phase integrity to permit their evaluation as CVD precursors. These, and related, results are presented herein.
展开▼
