Phase transition in bottom-up BaTiO3 films on Si

The phase transition was electrically investigated in (100)-oriented BaTiO3 thin and thick films deposited on Si substrate using double alkoxide solutions. Changes of the dielectric constant as a function of temperature in the range of -200-200 degrees C indicate that the transition from paraelectric to ferroelectric phase takes place around at 100 degrees C instead of 130 degrees C for single crystals. The broad peak of the dielectric constant shifted to lower temperatures and the behavior was associated with the crystallinity, orientation degree, and microstructure of the films. A highly (100)-oriented columnar BaTiO3 thin film with thickness of 280 nm exhibited two transitions at 0 and 100 degrees C from orthorhombic to tetragonal and tetragonal to cubic, respectively, while the 1 mu m thick BaTiO3 film with a combined structure consisted of columnar and granular grains showed a transition at 105 degrees C. (C) 2007 American Institute of Physics.