Apatite formation behavior on bio-ceramic films prepared by MOCVD

Calcium titanate (CaTiO₃), α-tricalcium phosphate (α-TCP) and hydroxyapatite (HAp) films were prepared by metal-organic chemical vapor deposition (MOCVD) using Ca(dpm)₂, Ti(O-i-Pr) ₂(dpm)₂ and (C₆H₅O)₃PO precursors. The phases, composition and surface morphology of these films changed depending on substrate temperature (T_sub), total pressure (P_tot) and molar ratio of each precursors (R_Ca/Ti, R _Ca/P). The surface morphology of CaTiO₃ films changed from granular structure to cauliflower-like texture, and its cross-sectional morphology changed from dense to columnar structure with increasing T _sub. α-TCP and HAp films had granular surface and dense cross-sectional morphology. CaTiO₃, α-TCP and HAp films were immersed in a Hanks' solution for 28 d. Apatite formation rate strongly depended on the surface morphology of CaTiO₃ film, and apatite covered CaTiO₃ film having a granular surface after 4 w while CaTiO ₃ film having a cauliflower-like texture after 3 d. Apatite covered α-TCP films after 14 d and HAp films after 6 h, respectively. HAp films prepared by MOCVD were promising as bone conductive materials.