PbTiO3-covered ZnO nanorods were grown on Al2O3 by metalorganic chemical vapor deposition (MOCVD), and their crystalline orientation was investigated by x-ray diffraction (XRD). Structural analysis by scanning electron microscopy and XRD revealed that the hexagonal ZnO nanorods had -side facets. XRD analysis of PbTiO3 thin films on ZnO/Al2O3revealed that PbTiO3 was epitaxially grown on ZnO, showing 6 variants of crystallites with the c-axis tilted either 27o or 69o from the surface normal to the ZnO plane. Effective piezoelectric coefficients calculated for the 27o and 69o-crystallites using piezoresponse force microscopy confirm that deformation of nanorods and nanotubes contributed to the large electrically-induced strain along the radial direction.

BiFeO3 (BFO) thin films have been deposited on SrRuO3/SrTiO3 (001) substrate by using ion beam sputtering process. At low oxygen partial pressure of 11 m Pa, rhombohedral and large c/a mixed phase thin film have been obtained in spite of rhombohedral BFO single phase formation at high oxygen partial pressure of 73 mPa. From wide area 2θ-Ψ mappings, diffraction peaks from large c/a phase BFO thin film were obtained with the same extinction rule as those of rhombohedral BFO. Reciprocal space mappings around BFO (003) and BFO (103) spots indicate that lattice parameters of large c/a phase BFO were a = 0.381 nm and c = 0.461 nm (c/a =1.22), respectively. Moreover ferroelectric domain switching could be observed in both of rhombohedral BFO and mixed phase BFO thin films.

We have investigated relationships between leakage current and microstructure or domain structure of BiFeO3 (BFO) thin films, and leakage current mappings of BFO thin films have been performed by current sensitive AFM. 350-nm-thick and 250-nm-thick BFO thin films were prepared on Pt/TiO2/SiO2/Si substrate by pulsed laser deposition (PLD) and chemical solution deposition (CSD), respectively. Average grain size of PLD-BFO thin film is about 480 nm, which is the same as the film thickness. From the leakage current mapping at a bias voltage of -16 Vdc, leakage current of the BFO thin film flows through not only grain boundary but also the grain itself. On the other hand, CSD-BFO thin film shows rosette structure and small size grains. From the leakage current mapping at a bias voltage of -10 Vdc, leakage current flows along boundaries of the rosette structures. These results indicate that leakage current of BFO strongly depends on its microstructure.

An Influence of stress of crystal structure of polycrystalline BiFeO3 (BFO) thin film on membrane structure has been investigated. To confirm the stress dependence of the crystal structure, reciprocal space mapping measurement of polycrystalline BFO thin films on Pt (200 nm)/TiO2 (50 nm)/SiO2 (600 nm)/Si (625 μm) plate substrate and Pt (200 nm)/TiO2 (50 nm)/SiO2 (600 nm)/Si (15 μm) membrane substrate have been performed. These BFO thin films have been prepared by pulsed laser deposition (PLD). The obtained BFO thin films were polycrystalline and mainly oriented to (001) and (110) plane. From reciprocal space mapping measurement, (110) oriented BFO grains on Pt/TiO2/SiO2/Si (15 μm) membrane substrate were expanded perpendicularly to the film plane about 0.15% and compressed in parallel to the film plane about 0.7% comparing to that on Pt/TiO2/SiO2/Si (625 μm) plate substrate. And (001) oriented BFO grains on the Pt/TiO2/SiO2/Si membrane substrate were expanded about 0.20% perpendicularly to the film plane and compressed about 1.3% in parallel to the film plane comparing to that on Pt/TiO2/SiO2/Si (625 μm) plate substrat

We report on microstructure and ferroelectric properties of ultrathin PbTiO3 films epitaxially grown on SrTiO3(100), La-doped SrTiO3(100) and SrRuO3/SrTiO3(100) by MOCVD. High angle annular dark field scanning transmission electron microscopy, atomic force microscopy, x-ray diffraction and x-ray reflectivity measurements demonstrated that 1-20 monolayer (ML)-thick epitaxial PbTiO3 films had high-crystallinity, atomically flat surface and sharp interface at an atomic scale. The epitaxial relationship and thickness were also confirmed by these methods. Kelvin force probe microscopy and contact resonance piezoresponse force microscopy revealed that a 7ML (2.7nm)-thick PbTiO3 film grown on SrRuO3/SrTiO3 had the ferroelectric polarization.

A novel liquid iridium precursor (1,3-cyclohexadiene)(ethylcyclopentadienyl)iridium, Ir(EtCp)(CHD), was synthesized and its physical properties were examined. Ir(EtCp)(CHD) exhibited enough vapor pressure (0.1 Torr/75°C), excellent volatility and adequate decomposition temperature. Characteristics of the Ir films deposited using Ir(EtCp)(CHD) and the conventional Ir precursor (1,5-cyclooctadiene)(ethylcyclopentadienyl)iridium, Ir(EtCp)(COD), by metal-organic chemical vapor deposition (MOCVD) method were compared. Ir films grown using Ir(EtCp)(CHD) showed shorter incubation time and higher nucleation density than those of films using Ir(EtCp)(COD).

Using the MOCVD process to produce Pb(Zr, Ti)O3 (PZT) thin films, control of the film stoichiometry and crystalline phase was achieved. The PZT films obtained showed good step coverage, 67%. Uniform PZT and PLZT thin films with a variation of film thickness of less than ±1.5% were successfully obtained on a 6–8 inch silicon wafer. For the evaluation of the crystallinity and epitaxial relationship of the PZT thin films, the total reflection X-ray diffraction (TRXD) method was used for the first time. Using TRXD, the in-plane orientations of PZT and Pt in PZT/Pt/MgO were evaluated. The growth mechanism of PbTiO3 and PZT thin films at the initial growth stage was also investigated using an atomic force microscope (AFM). The switching characteristics of PZT capacitors using Ir and IrO2 electrodes for memory device applications were also investigated and a PZT capacitor with no fatigue up to a switching cycle of 1011 was obtained.

The advantages of MOCVD for the growth of Pb(Zr,Ti)O3 (PZT) and (Pb,La)(Zr,Ti)O3(PLZT) thin films were discussed, with emphasis on the controllability of film composition, crystalline structure and electrical properties. The possibilities of lowering the processing temperature and scaling up the process to commercial-based production were investigated. The preparation of PZT films and electrodes with a specific focus on improving the I-V and fatigue characteristics was also investigated.

Ferroelectric Pb(Zr,Ti)O3(PZT) films with a perovskite phase were successfully grown by MOCVD using a 6 inch wafer CVD system. A two step growth process was proposed to obtain perovskite PZT films at high gas supplying ratios of [Zr]/([Zr]+[Ti]). The electrical properties of the PZT films obtained were measured. Large area growths of PZT films were carried out and the uniform films could be grown on the entire area of a 6 inch Si wafer. It was also found that the step coverage characteristic of the films grown by MOCVD was good.