Preparation of ferroelectric BaTiO3 thin films by metal organic chemical vapour deposition
Polycrystalline BaTiO3 thin films have been successfully prepared on (100) silicon substrates at temperatures under 600° C by metal organic chemical vapour deposition using barium acetylacetonate and diisopropoxy-titanium-bis-(acetylacetonate). To vaporize the barium acetylacetonate, which is nonvolatile under 300° C and thermally unstable, an ultrasonic spraying technique was used. The substrate temperature had a great influence on the structure and composition of films and the single-phase BaTiO3 films could be prepared at 500° C. At temperatures above 550° C the reaction between the film and the silicon substrate occurred to a large extent. The polarization-electric field (P-E) hysteresis loops and counter-clockwise direction of hysteresis in the high-frequency (1 MHz)C-V characteristics indicate that the BaTiO3 films deposited on silicon using the present method are ferroelectric.