A novel approach to synthesizing calcium copper titanate thin films with giant dielectric constants

Thin films of CaCu3Ti4O12 (CCTO) were grown on LaAlO3 substrate by metalorg. chem. vapor deposition (MOCVD) of Ti(tmhd)2(O-i-Pr)2, Ca(hfa)2-tetraglyme, and Cu(tmhd)2 (Htmhd = 2,2,6,6-tetramethyl-3,5-heptadione; Hhfa = 1,1,1,5,5,5-hexafluoro-2,4-pentadione; tetraglyme = 2,5,8,11,14-pentaoxapentadecane). The best growth conditions were: use of the above precursors at a 1:1:3 Ca-Cu-Ti ratio, 100 cm3/min Ar carrier gas with 200 cm3/min O2, 1 h deposition time, and 900° in-situ annealing in an O2-contg. gas for 1 h. The CCTO films were aligned with their c axis normal to the substrate surface. Lattice consts. of the films were : (a) 7.416 ± 0.002 Å, and (c) 7.440 ± 0.002 Å.