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We report conformal deposition of both RuO2 electrodes and PbZrxTi1-xO3 (PZT) capacitors in submicron Si trenches through the same in situ liquid source mist processing. The step coverage for the RuO2 electrodes is 75% at 225 °C. After electroding, we deposited Pb(Zr,Ti)O3 thin films and nanotubes using the same apparatus with remanent polarization of ∼15 μC/cm2. The step coverage was 59% on the sidewall and 79% on the bottom wall. Electrical testing showed charge storage (capacitance/trench) was 13±2 pF, with a breakdown voltage of 11.3±0.2 V and dielectric constant [variant_greek_epsilon]=166±30. This shows that a single inexpensive processing can produce fully electroded dynamic random access memory trenched capacitors with high aspect ratios and commercial electrical performance. [ABSTRACT FROM AUTHOR]

ZnO thin films were deposited on SiO2/Si(100) and single-crystal MgO substrate using pulsed laser deposition. High-quality ZnO thin films were fabricated on both substrates successfully. Interdigital transducer-shaped Al electrodes were used for measuring electrical properties. Electrical current as a function of voltage, temperature-dependent I-V, and impedance of ZnO thin films were measured. ZnO thin films on MgO substrate show ohmic behavior. On the other hand, ZnO thin films on SiO2/Si(100) substrate show good thermal stability but Schottky-like diode behavior. [ABSTRACT FROM AUTHOR]

A modification of liquid source misted chemical deposition process (LSMCD) with heating mist and substrate has developed, and this enabled to control mist penetrability and fluidity on sidewalls of three-dimensional structures and ensure step coverage. A modified LSMCD process allowed a combinatorial approach of Pb(Zr,Ti)O3 (PZT) thin films and carbon nanotubes (CNTs) toward ultrahigh integration density of ferroelectric random access memories (FeRAMs). The CNTs templates were survived during the crystallization process of deposited PZT film onto CNTs annealed at 650°C in oxygen ambient due to a matter of minute process, so that the thermal budget is quite small. The modified LSMCD process opens up the possibility to realize the nanoscale capacitor structure of ferroelectric PZT film with CNTs electrodes toward ultrahigh integration density FeRAMs. [ABSTRACT FROM AUTHOR]

We have found that a hafnia precursor (hafnium bis-isopropoxy bis-thd) for chemical solution deposition (CSD) yields a crystallization temperature ca . 80°C above that usually found for CSD film deposition (e.g., 521°C for Hf-butoxide). These results are considered in terms of two models: the coordination oligomerism model of Turova and Yanovskaya, and a model of competing surface assembly mechanisms from monomeric precursors; although both are compatible with Raman data on film crystallisation temperatures, DTA/TG results on bulk samples support the competing surface assembly model, as do differing values of surface roughness for the different precursors. Implications for commercial production of hafnia gate oxides capable of withstanding conventional FET front-end processing are emphasised. [ABSTRACT FROM AUTHOR]

A review is given of ceramic and single-crystal thin film ferroelectric oxides, emphasizing perovskite phases, together with some new developments on hafnia films. It is shown that single-crystal barium titanate films behave as bulk down to at least 77 nm, with no finite size effects, no phase transition temperature shifts, and no dielectric peak broadening or change from first- to second-order transitions, suggesting that the gradient defect model of Bratkovsky and Levanyuk correctly describes such effects as extrinsic in experimental studies of equally thin ceramic thin films. In ceramic barium–strontium titanate (BST) thin films, it is shown that there is also no intrinsic broadening or shifts in phase transitions, with sharp, unshifted, bulk-like transitions observed only as re-entrant upon warming from cryogenic temperatures; this shows that phase transitions in ceramic thin films are dominated by kinetics and not thermodynamics and are definitely not equilibrium measurements. At high fields (>1 GV/m), the films exhibit space charge-limited conduction; no variable-range hopping is observed, contrary to recent studies on SrTiO3. Some novel, unconventional switching processes are discussed, comparing the “perimeter effect” (non-equilibrium, ballistic) with Molotskii's equilibrium model. Theory and experiment are described for [3D] nanotubes, nanorods, and nano-ribbons (or micro-ribbons). The layered-structure-perovskite–pyrochlore conversion in bismuth titanate is described together with the PbO+TiO2 phase separation in lead zirconate titanate during electrical breakdown, as are novel HfO2 precursors that demonstrate enhanced temperature crystallization from the amorphous state and hence commercial advantages for front-end processing. [ABSTRACT FROM AUTHOR]

The International Roadmap for Ferroelectric Memories requires three-dimensional integration of high-dielectric materials onto metal interconnects or bottom electrodes by 2010. Here, we demonstrate the possibility of conformally coating carbon nanotubes with high-dielectric oxide as a first step toward ultrahigh integration density of three-dimensional ferroelectric random access memories. [ABSTRACT FROM AUTHOR]