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The list covers all scientific references related to Atomic Layer Deposition from 1970 to November 2007 (3403 records).

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10 Entries displayed at random.

de Melo, O Larramendi, EM Duart, JMM Velez, MH Stangl, J Sitter, H , Structure and growth rate of ZnTe films grown by isothermal closed space sublimation , Journal of crystal growth 2007 , 307 , 253 -258
Abstract: Results on isothermal closed space sublimation (ICSS) of ZnTe using different experimental conditions are presented. Wide ranges of exposure and purge times were used to study the properties of the adsorption and desorption processes in this material. Moreover, the atmosphere and the type of substrates were also varied. It was found that epitaxial ZnTe layers are always obtained in either [11 1] or [10 0] oriented GaAs substrates regardless the used gas atmosphere. In contrast, samples grown on [10 0] oriented Si substrates showed powder-like X-ray diffraction features with a strong preferential orientation in the [1 1 1] direction. In both kinds of substrates, there were obtained growth rates considerably larger than one monolayer per cycle for samples grown with large exposure times to the sources. The influence of different process like gas absorption in the substrate holder, gas transport in the substrate compartment and multilayer adsorption on these large growth rates is discussed.

Klepper, KB Nilsen, O Fjellvag, H , Epitaxial growth of cobalt oxide by atomic layer deposition , Journal of crystal growth 2007 , 307 , 457 -465
Abstract: Highly oriented thin films of cobalt oxide were made by the atomic layer deposition (ALD) technique, using Co(thd)(2) (Hthd = 2,2,6,6-tetramethylheptan-3,5-dione) and ozone as precursors. Films were deposited on single-crystalline substrates of MgO(1 0 0), alpha-Al2O3(0 0 1), and SrTiO3(1 0 0). Epitaxial growth has been established with the following orientations: (0 0 1)[1 0 0]Co3O4 parallel to(0 0 1)[1 0 0]MgO, (1 1 1)[1 1 1]Co3O4 parallel to(0 0 1)[0 0 1]alpha-Al2O3, and (0 0 1)[1 0 0]SrTiO3. The resulting texture was studied as function of deposition temperature in the range 138-283 degrees C for MgO(1 0 0) and 186-283 degrees C for the remaining substrates. The topography and morphology of the films were investigated by atomic force microscopy (AFM), and in selected cases scanning electron microscopy. The specific electronic resistivities of as-deposited films grown on the various substrates were measured to be from 0.8 to 85 Omega cm.

Fan, HJ Gosele, U Zacharias, M , Formation of nanotubes and hottow nanopartictes based on kirkendatt and diffusion processes: A review , Small 2007 , 3 , 1660 -1671
Abstract: The Kirkendall effect is a consequence of the different diffusivities of atoms in a diffusion couple causing a supersaturation of lattice vacancies. This supersaturation may lead to a condensation of extra vacancies in the form of so-called "Kirkendall voids" close to the interface. On the macroscopic and micrometer scale these Kirkendall voids are generally considered as a nuisance because they deteriorate the properties of the interface. In contrast, in the nanoworld the Kirkendall effect has been positively used as a new fabrication route to designed hollow nano-objects. In this Review we summarize and discuss the demonstrated examples of hollow nanoparticles and nanotubes induced by the Kirkendall effect. Merits of this route are compared with other general methods for nanotube fabrication. Theories of the kinetics and thermodynamics are also reviewed and evaluated in terms of their relevance to experiments. Moreover, nanotube fabrication by solid-state reactions and non-Kirkendall type diffusion processes are covered.

Escrig, J Daub, M Landeros, P Nielsch, K Altbir, D , Angular dependence of coercivity in magnetic nanotubes , Nanotechnology 2007 , 18 , 445706 -445706
Abstract: The nucleation field for infinite magnetic nanotubes, in the case of a magnetic field applied parallel to the long axis of the tubes, is calculated as a function of their geometric parameters and compared with those produced inside the pores of anodic alumina membranes by atomic layer deposition. We also extended this result to the case of an angular dependence. We observed a transition from curling-mode rotation to coherent- mode rotation as a function of the angle in which the external magnetic field is applied. Finally, we observed that the internal radii of the tubes favors the magnetization curling reversal.

Chen, Y Wu, QS Ding, YP , Synthesis and characterization of ZnS nanotubes with crossed-channels , Journal of the brazilian chemical society 2007 , 18 , 924 -927
Abstract: ZnS nanotubes with crossed-channels have been synthesized successfully using a hydrothermal method. A novel hydrothermal reaction of simultaneous solvent-oxidation-hydrolysis has been developed using Zn powder, H2O and NH2CSNH2 as reagents. TEM images show that each branch of the channels is about 400-500 nm long. The inner diameter is 55 nm, the outer diameter is 70 mn, and the interlayer spacing is about 7 nm. XRD data show that the product is well-crystallized in the cubic Sphalerite phase. The peak appears at 293 nm in the UV-Vis absorption spectrum, which is about 50 nm blue shifted from the bulk counterpart. The photoluminescence spectrum of ZnS nanotubes shows that the emission peak occurs at 409 nm when excited at 365 nm.

Dezelah, CL Wiedmann, MK Mizohata, K Baird, RJ Niinisto, L Winter, CH , A pyrazolate-based metalorganic tantalum precursor that exhibits high thermal stability and its use in the atomic layer deposition of Ta2O5 , Journal of the american chemical society 2007 , 129 , 12370 -+
Abstract: The atomic layer deposition (ALD) growth of Ta2O5 thin films was investigated using tert -butylimidotris(3,5-di- 0 tert -butylpyrazolato)tantalum and ozone as precursors at deposition temperatures between 250 and 500 degrees C. The process provided uniform films and exhibited a large ALD window between 300 and 450 degrees C, in which a constant growth rate of 0.30 angstrom/cycle was observed. Surface-limited growth was confirmed at 325 degrees C, as evidenced by a constant growth rate with increasing precursor dose as delivered by longer pulse lengths. Furthermore, the thickness of films deposited at 325 degrees C varied linearly with the number of deposition cycles, which demonstrates good thickness control typical of ALD growth. The process provided stoichiometric Ta2O5 films with carbon, hydrogen, and nitrogen levels of <= 1.0 <= 1.9 and <= 0.9 atom %, respectively, within the ALD temperature window as determined by time-of-flight elastic recoil detection analysis. X-ray photoelectron spectroscopy measurements were consistent with the presence of Ta(V) and a stoichiometry of Ta2O5, with impurity elements below detection limits. All films were amorphous as deposited as determined by X-ray diffraction.

Pan, S Ding, SJ Huang, Y Huang, YJ Zhang, DW Wang, LK Liu, R , High-temperature conduction behaviors of HfO2/TaN-based metal-insulator-metal capacitors , Journal of applied physics 2007 , 102 , 073706 -073706
Abstract: High-temperature (similar to 90-150 degrees C) conduction mechanisms of metal-insulator-metal (MIM) capacitors with atomic-layer-deposited HfO2 dielectric are studied. In the low field range, the Schottky emission current is dominant, and the deduced dielectric constant is close to the static one of HfO2. In the high field range, the resulting leakage current complies with the Poole-Frenkel (PF) emission, which is demonstrated by the fact that the extracted dielectric constant equals the optical frequency one (i.e., square of refractive index) of HfO2. The underlying mechanisms are discussed based on carrier velocities under different electric fields. Further, the deduced Schottky barrier height is similar to 0.251-0.274 eV in the low field range, which relates to the contributions from high density traps in the HfO2 film and the nonideal TaN/HfO2 interface, etc. The extracted trap potential well depth for the PF effect is similar to 1.11-1.37 eV in the high field range.

Lee, HJ Kim, GH Lee, K Hwang, CS , Initial growth behavior of a lead oxide thin film on Ir substrates by atomic layer deposition , Electrochemical and solid state letters 2007 , 10 , G89 -G92
Abstract: Lead oxide thin films were deposited on Ir/IrO2/SiO2/Si substrates by atomic layer deposition at 200 degrees C using lead bis(3-N,N-dimethyl-2-methyl-2-propanoxide) and H2O as the Pb precursor and oxidant, respectively. The growth rate was 0.036 nm/cycle up to a thickness of similar to 1 nm but decreased to 0.011 nm/cycle with further increases in thickness. Atomic force microscopy showed that the surface morphology changed slightly with film growth, but this variation cannot explain the large change in growth rate. X-ray photoelectron spectroscopy showed a distinct difference in the chemical composition [O/(Pb+Ir) ratio] between the two thickness regions, which might be responsible for the large discrepancy in growth rate.

Ren, J Sun, B Zhang, DW , Density functional study of initial HfCl4 adsorption and decomposition reactions on silicon surfaces with SiON interfacial layer , Applied surface science 2007 , 253 , 9148 -9153
Abstract: The initial adsorption and decomposition of HfCl4 on silicon surfaces with different types of SiON interfacial layers are investigated using density functional theory. We find that the reactions of HfCl4 on both the hydroxylated and nitrided silicon surfaces proceed through similar reaction pathways. By comparison of the reaction energies of HfCl4 with the hydroxyl and amino surface sites, we find that it is both kinetically and thermodynamically favorable for the reactions of HfCl4 on hydroxyl site of silicon substrates. Comparing with the adjacent bridging oxygen, we also find that the neighboring hydroxyl can facilitate the adsorption of HfCl4 on the amido surface site. Also, it is more kinetically and thermodynamically favorable for the reaction of HfCl4 with bridging NH site than that with NH2 site.