Influence of thermal decomposition behavior of titanium precursors on (Ba,Sr)TiO3 thin films

An N-alkoxy-β-ketoiminato titanium complex, Ti(2meip)2 (2meip = 4-(2-methylethoxy)imino-2-pentanoate), was investigated as a Ti precursor for BST thin film growth, and compared with Ti(thd)2(OiPr)2 (thd = 2,2,6,6-tetramethyl-3,5-heptandionate) and Ti(mpd)(thd)2 (mpd = 2-methyl-2,4-petanedioxy) in terms of thermal decomposition properties. It shows a moderate volatility, chemical and thermal stability, and a simple decomposition behavior above 315°C. The deposited BST films with this novel precursor by liquid delivery metal-organic chemical vapor deposition (LS-MOCVD) demonstrate ultra-smooth surface without humps or hazy appearance, and relatively less variation of the titanium composition along the deposition temperature as compared with other titanium precursors, presumably due to easy and clean decomposition behavior of Ti(2meip)2. The as-deposited BST films are beginning to crystallize at 430°C without additional annealing process