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°C indicate that the transition from paraelectric to ferroelectric phase takes place around at 100°C instead of 130°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 280nm exhibited two transitions at 0 and 100°C from orthorhombic to tetragonal and tetragonal to cubic, respectively, while the 1μm thick BaTiO3 film with a combined structure consisted of columnar and granular grains showed a transition at 105°C.