Low Temperature Hydrothermal Synthesis and the Growth Kinetics of BaTiO3 Films on TiN/Si, Ti/Si, and Bulk-Ti Substrates

Abstract

Barium titanate (BaTiO3) films were prepared on TiN- and Ti-coated Si as well as bulk-Ti substrates by a hydrothermal method at temperatures below 100 degrees C. Both titanium nitride and titanium films prepared by dc sputtering exhibited nanograins, while bulk titanium possessed micrograins. These substrates were soaked in a mixture of Ba(CH3COO)(2) and NaOH alkaline solutions at temperatures below 100 degrees C for various times. X-ray diffraction patterns show that cubic BaTiO3 films were successfully formed on TiN/Si and Ti/Si without BaCO3 contamination over a period of 2 h at temperatures as low as 45 and 52.5 degrees C, respectively, while the formation of BaTiO3 on bulk Ti required temperatures exceeding 60 degrees C for the same reaction time. Field-emission-scanning electron microscopy revealed that BaTiO3 films exhibited a nanospherical-like morphology. The kinetic formation diagrams of BaTiO3 films on the substrates were generated. The growth rate of BaTiO3 on TiN/Si was much faster than that on Ti/Si and bulk Ti, which was due to the different nature of the titanium source. The growth kinetics was also analyzed and discussed. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3367745] All rights reserved.