RADIO-FREQUENCY-SPUTTERED TETRAGONAL BARIUM-TITANATE FILMS ON SILICON

Polycrystalline films of BaTiO//3 displaying electron diffraction patterns identical to that of bulk tetragonal BaTiO//3 and ferroelectric properties are regularly observed for BaTiO//3 films thicker than 1000 A rf-sputtered deposited at 5 A/min onto silicon substrates at temperatures above 500 degree C. A severe interaction problem between the silicon substrate and the BaTiO//3 contaminates the film, but can be avoided by growing a passivation barrier of SiO//2 on the silicon substrate before depositing BaTiO//3. Despite a coefficient of thermal expansion mismatch between BaTiO//3 and silicon, thin films with good electrical insulation properties can be obtained by reducing the substrate temperature during the deposition by 7. 0 degree C/min to a final substrate temperature of 200 degree C.