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Pr1–xCaxMnO3 thin films have been deposited through an in situ metal organic chemical vapor deposition (MOCVD) process using a molten multi-metal source, consisting of the Pr(hfa)3·diglyme, Ca(hfa)2·tetraglyme, and Mn(tmhd)3 precursor mixture on single crystal substrates such as LaAlO3 (001) and MgO (001). Optimization of processing parameters has allowed the deposition of homogeneous thin films in morphology, composition, and thickness. The effect of substrate has been assessed in relation to structure and morphology. Field emission scanning electron microscope of a Pr0.7Ca0.3MnO3 film deposited at 1000 °C on MgO (001).

Metal-Organic Chemical Vapor Deposition (MOCVD) has been applied to the fabrication of BiFeO 3 on dielectric SrTiO 3 and conducting SrTiO 3 :Nb (100) substrates. Films have been deposited using a mixed bi-metallic source, consisting of Bi(phenyl) 3 and Fe(tmhd) 3 , (phenyl = -C 6 H 5, H-tmhd = 2,2,6,6-tetramethyl-3,5-heptandione) precursor mixture. The chemical, structural and morphological characterizations of films have been carried out by energy dispersive X-ray analysis, X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Local piezoelectric properties have been investigated by piezoresponce force microscopy (PFM) and piezoelectric force spectroscopy (PFS). Structural and morphological characterizations point to the formation of homogeneous and flat surfaces for BiFeO 3 films. Different ferroelectric/piezoelectric domains have been observed depending on the structure/morphology of the samples.

Thin films of CaCu3Ti4O12 (CCTO) are successfully deposited by metal-organic (MO)CVD on (001)SrTiO3 substrates. An interesting approach, based on a molten multi-component precursor source, is applied. The molten mixture consists of the Ca(hfa)2 center dot tetraglyme, Ti(tmhd)2(OiPr)2, and Cu(tmhd)2 [Hhfa?=?1,1,1,5,5,5-hexafluoro-2,4-pentanedione; tetraglyme?=?2,5,8,11,14-pentaoxapentadecane; Htmhd?=?2,2,6,6-tetramethyl-3,5-heptandione; OiPr?=?iso-propoxide] precursors. It is also found that, in the present case of a relatively large lattice mismatch (similar to 5%), the epitaxial growth can be achieved by a careful optimization of deposition parameters. Film structural and morphological characterization is carried out using several techniques; X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). A complete comparison between films deposited by two main processes is carried out in order to understand the kinetic and thermodynamic issues involved in the MOCVD epitaxial growth.

NiO thin films were grown through metalorganic chemical vapour deposition (MOCVD) on quartz and LaAlO3 (001) single crystal substrates. Two different volatile and thermally stable nickel β-diketonate adducts, Ni(hfa)2·tmeda and Ni(tta)2·tmeda [H-hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentandione; tmeda = N,N,N′,N′-tetramethylethylendiamine, Htta = 2-thenoyltrifluoroacetone], were applied as precursors for NiO film growth. The comprehensive study, applying two different precursors and changing the processing parameters, allowed for morphological control of the deposited NiO films. The AFM analyses indicated different values of roughness for NiO films obtained from the two different precursors and those from Ni(tta)2·tmeda showed a lower roughness. In addition, UV-Vis and ellipsometric measurements on NiO films grown from the Ni(tta)2·tmeda show higher transparency, fewer defects/impurities, better crystallinity and a higher refractive index than films deposited using the Ni(hfa)2·tmeda source. Raman spectroscopy confirmed the antiferromagnetic nature of the NiO layers. Work functions, around 5.1 eV, were measured by Kelvin Probe Force Microscopy for NiO films grown from Ni(tta)2·tmeda. The relationship between the precursor/substrate nature and film properties allowed us to define the best precursor and conditions for the MOCVD growth of good quality NiO films.

Calcium-doped praseodymium manganite films (Pr0.7Ca0.3MnO3, PCMO) were prepared by metal-organic chemical vapor deposition (MOCVD) on SrTiO3 (001) and SrTiO3 (110) single-crystal substrates. Structural characterization through X-ray diffraction (XRD) measurements and transmission electron microscopy (TEM) analyses confirmed the formation of epitaxial PCMO phase films. Energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) characterization was used to confirm lateral and vertical composition and the purity of the deposited films. Magnetic measurements, obtained in zero-field-cooling (ZFC) and field-cooling (FC) modes, provided evidence of the presence of a ferromagnetic (FM) transition temperature, which was correlated to the transport properties of the film. The functional properties of the deposited films, combined with the structural and chemical characterization collected data, indicate that the MOCVD approach represents a suitable route for the growth of pure, good quality PCMO for the fabrication of novel spintronic devices.

The increasing need to miniaturize capacitor devices is demanding for progressively higher dielectric constant materials. Recent studies have demonstrated that the calcium copper titanate, CaCu3Ti4O12 (CCTO), single crystals and ceramics possess impressive dielectric constant values of about 10 working at 1 MHz which remain constant in the 100-600K temperature range and slightly depend upon work frequency in the 10-10 Hz range. Fabrication of thin films becomes now a required issue to understand their properties and evaluate potentialities for device integration. The synthesis of a multi-element oxide phase often requires considerable efforts to define the appropriate deposition conditions for the fabrication of high quality thin films and in particular the MOCVD growth process depends critically on the availability of volatile, thermally stable precursors. CaCu3Ti4O12 (CCTO) thin films have been successfully deposited on LaAlO3 (100) single substrates and on Pt/TiO2/SiO2/Si(100) stacks using Metal Organic Chemical Vapor Deposition technique, a suitable method even for large-scale production. A novel approach based on a molten multi-component precursor source has been applied. The molten mixture consists of the Ca(hfa) 2 •tetraglyme, Ti(tmhd)2(i-Opr)2, and Cu(tmhd)2 [Hhfa= 1,1,1,5,5,5-hexafluoro-2,4-pentanedione; tetraglyme= 2,5,8,11,14-pentaoxapentadecane; Htmhd= 2,2,6,6-tetramethyl-3,5-heptandione; i-Opr = isopropoxide] precursors. 6-8 Film complete structural and morphological characterizations have been carried out by several techniques [X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM)]. The in-situ deposited CCTO (001) films on LaAlO3 (001) substrates are of high quality as evidenced by their inplane and out-of-plane alignments investigated using Xray and electron transmission diffraction patterns. CCTO films grown on Pt/TiO2/SiO2/Si(100) industrial substrates are polycrystalline (Figure 1) and present more disordered morphologies (Figure 2). Moreover, the electrical characterization at micro (Figure 2) and nanometer scale has been performed. The permittivity imaging provided at nanometer scale by Scanning Impedance Microscopy provided a correlation between the physical properties and structural characteristics. The nano impedance modulus and phase have been detected and the permittivity of the single CCTO layer has been calculated to be about 8000 at 90 kHz. Figure 1. XRD of CCTO polycrystalline films on Pt electrode and CCTO unit cell as inset.