Application of rapid thermal process to solution-processed Ti-silicate films for enhancing permittivity without losing amorphous nature

Nanoscale thick Ti-silicate films were synthesized by the solution process on Si(100) substrates, followed by post annealing of rapid thermal process (RTP). The film retained its amorphous structure with a remarkably enhanced permittivity (k) value: the k values of the Ti-silicate layer and overall film were increased from 8.6 to 16.2 and from 4.9 to 9.7, respectively, by performing RTP at 700 °C for 1 min. The k value of the interfacial layer between the Ti-silicate and Si was almost unchanged (∼7) after RTP. The FT-IR and XPS analyses indicated that the films had Ti–O–Si bonding relating to the segregated phases of Ti- and Si-rich silicates before RTP. The segregated nature of the sample before RTP was probably due to the different hydrolysis rates of the Si and Ti precursors and/or nanoscale thickness. The degree of segregation further increased after RTP, resulting in a significant improvement of the k value of the Ti-silicate.