Control of Heteroepitaxial Growth of CaCu3Ti4O12 Films on SrTiO3 Substrates by MOCVD


  • Authors thank the European Community for the financial support under the project NUOTO (New Materials with Ultrahigh k dielectric constant for tomorrow wireless electronics) NMP3-CT-2006-032644.


Thin films of CaCu3Ti4O12 (CCTO) are successfully deposited by metal-organic (MO)CVD on (001)SrTiO3 substrates. An interesting approach, based on a molten multi-component precursor source, is applied. The molten mixture consists of the Ca(hfa)2•tetraglyme, Ti(tmhd)2(OiPr)2, and Cu(tmhd)2 [Hhfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedione; tetraglyme = 2,5,8,11,14-pentaoxapentadecane; Htmhd = 2,2,6,6-tetramethyl-3,5-heptandione; OiPr = iso-propoxide] precursors. It is also found that, in the present case of a relatively large lattice mismatch (∼5%), the epitaxial growth can be achieved by a careful optimization of deposition parameters. Film structural and morphological characterization is carried out using several techniques; X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). A complete comparison between films deposited by two main processes is carried out in order to understand the kinetic and thermodynamic issues involved in the MOCVD epitaxial growth.