Oriented PbTiO3 thin films were successfully grown on (200)-oriented Pt/SiO2/Si by metalorganic chemical vapor deposition at low temperature range from 350 °C to 400 °C, using β-diketonate complex of Pb(tmhd)2 and titanium isopropoxide as source precursors. Dependences of orientation and formation of crystalline PbTiO3 phase on Pb/Ti ratio and substrate temperature was investigated. Crystalline phases and preferred orientations were determined by X-ray diffraction technique, and surface morphology was identified with scanning electron microscopy. As the deposition temperature was raised from 350 °C to 400 °C at two fixed Pb/Ti ratios of 3.3 and 5.0, structures of PbTiO3 films transformed from amorphous to polycrystalline and preferred orientation changed from random to  parallel to the surface. Similar results were also observed in the films deposited at 400 °C with the increase of Pb/Ti ratio from 1.1 to 5.0. As the Pb/Ti ratio increased, the dielectric constant and current density increased due to crystallization of the PbTiO3 films. It is found that the control of excess Pb precursor amount through Pb/Ti ratio change is the key process parameter for the formation of crystalline PbTiO3 phase in the low temperature MOCVD process.
Bibliographical noteFunding Information:
This work was supported by Yonsei University Research Fund of 1999.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering