Chemical bath deposition of thin TiO2-anatase films for dielectric applications

Titania thin films were prepared on bare Si and Pt/Ti/SiO2/Si substrates by chemical bath deposition (CBD) from solutions of a titanium peroxo complex and subsequent calcinations at 350 and 700 degrees C, respectively. The CBD process allowed deposition on both uncoated and metal-coated Si substrates with the same deposition rate. Optimization of the annealing process yielded uniform and crack-free nanocrystalline anatase films. The influence of the film thickness, irradiation of visible light, measuring frequency, temperature and substrate on the dielectric properties will be discussed in the paper. Films with a final thickness of about 600 nm showed comparably high relative permittivity of 31.8 on silicon and of 52.7 on Pt/Ti/SiO2/Si substrates, respectively. The present route provides anatase thin films with higher dielectric constants than classical sol-gel routes and is therefore a promising candidate for potential applications in large scale integration.