Kim Euk Hyun, Lim Min Hyuk, Lah Myoung Soo, Koo Sang Man
Department of Chemical Engineering, Hanyang University, Seoul, 04763, Korea.
Dalton Trans. 2018 Feb 13;47(7):2415-2421. doi: 10.1039/c7dt04894g.
Heteroleptic titanium alkoxides with three different ligands, i.e., [Ti(OPr)(X)(Y)] (X = tridentate, Y = bidentate ligands), were synthesized to find efficient metal organic chemical vapor deposition (MOCVD) precursors for TiO thin films. Acetylacetone (acacH) or 2,2,6,6-tetramethyl-3,5-heptanedione (thdH) was employed as a bidentate ligand, while N-methyldiethanolamine (MDEA) was employed as a tridentate ligand. It was expected that the oxygen and moisture susceptibility of titanium alkoxides, as well as their tendency to form oligomers, would be greatly reduced by placing multidentate and bulky ligands around the center Ti atom. The synthesized heteroleptic titanium alkoxides were characterized both physicochemically and crystallographically, and their thermal behaviors were also investigated. [Ti(OPr)(MDEA)(thd)] was found to be monomeric and stable against moisture; it also showed good volatility in the temperature window between volatilization and decomposition. This material was used as a single-source precursor during MOCVD to generate TiO thin films on silicon wafers. The high thermal stability of [Ti(OPr)(MDEA)(thd)] enabled the fabrication of TiO films over a wide temperature range, with steady growth rates between 500 and 800 °C.
合成了具有三种不同配体的杂配钛醇盐，即[Ti(OPr)(X)(Y)]（X = 三齿配体，Y = 双齿配体），以寻找用于TiO薄膜的高效金属有机化学气相沉积（MOCVD）前驱体。乙酰丙酮（acacH）或2,2,6,6-四甲基-3,5-庚二酮（thdH）用作双齿配体，而N-甲基二乙醇胺（MDEA）用作三齿配体。预计通过在中心Ti原子周围放置多齿和庞大的配体，钛醇盐对氧气和水分的敏感性以及它们形成低聚物的倾向将大大降低。对合成的杂配钛醇盐进行了物理化学和晶体学表征，并研究了它们的热行为。发现[Ti(OPr)(MDEA)(thd)]是单体且对水分稳定；它在挥发和分解之间的温度窗口中也表现出良好的挥发性。该材料在MOCVD过程中用作单源前驱体，以在硅片上生成TiO薄膜。[Ti(OPr)(MDEA)(thd)]的高热稳定性使得能够在很宽的温度范围内制备TiO薄膜，在500至800°C之间具有稳定的生长速率。
