Microstructure control in MOCVD PZT thin films

It was shown that Pb(ZrxTi1-x)O-3 thin films (PZT) can be successfully deposited by metalorganic chemical vapor deposition (MOCVD) in a wide deposition temperature range starting from 400 degrees C to 600 degrees C. Variations in texture, morphology and grain size of the films as a function of process parameters were systematically investigated by x-ray diffraction (XRD) and scanning electron microscopy (SEM). The deposition temperature and gas composition in the reactor are the two key parameters that control the film microstructure. The accompanying changes in the ferroelectric properties with respect to the variations of the process parameters will also investigated. In addition, we found an interrelationship between the grain orientation and surface roughness of the films. Films with (111) preferred orientation are significantly smoother than the films with other preferred orientations. We also demonstrate, for the first time, fine grained PZT films with very low surface roughness, which show excellent electrical properties can be obtained by lowering the deposition temperature (e.g, 430 degrees C).