Chemical Vapor Deposition

Cover image for Chemical Vapor Deposition

October, 2003

Volume 9, Issue 5

Pages 227–285

    1. Contents: Chem. Vap. Deposition 5/2003 (pages 227–229)

      Article first published online: 23 OCT 2003 | DOI: 10.1002/cvde.200390014

    2. EUROCVD-14 and CVD XVI (pages 231–234)

      S. Krumdieck

      Article first published online: 23 OCT 2003 | DOI: 10.1002/cvde.200302008

      One of the largest CVD conferences ever held with over 230 papers and numerous posters was the combined fourteenth EUROCVD-14 and sixteenth international CVD conferences held in Paris are in the focus of this essay. The author does not only give an overview of sessions and highlights but also brings the atmosphere of the conference alive.

    3. Growth of Praseodymium Oxide Thin Films by Liquid Injection MOCVD Using a Novel Praseodymium Alkoxide Precursor (pages 235–238)

      H.C. Aspinall, J. Gaskell, P.A. Williams, A.C. Jones, P.R. Chalker, P.A. Marshall, J.F. Bickley, L.M. Smith and G.W. Critchlow

      Article first published online: 23 OCT 2003 | DOI: 10.1002/cvde.200304160

      Praseodymium oxide thin films are prepared using a new volatile precursor (for structure of precursor LiCl complex, see Figure) by liquid injection MOCVD. The oxide, a wide-bandgap (3.9 eV) and high-κ material, which is currently being investigated as a possible alternative to SiO2 films in silicon-based field-effect transistors, is deposited from [Pr(mmp)3] (mmp = OCMe2CH2OMe) in the presence of oxygen over the temperature range 350–600 °C.

    4. Low-Pressure Metal–Organic Chemical Vapor Deposition of Transparent and p-Type Conducting CuCrO2 Thin Films with High Conductivity (pages 238–240)

      S. Mahapatra and S.A. Shivashankar

      Article first published online: 23 OCT 2003 | DOI: 10.1002/cvde.200304147

      The growth of CuCrO2 films on glass substrate by LP-MOCVD is reported. Unlike nearly all transparent conducting oxides which exhibit only n-type conductivity, CuCrO2 crystalline thin films deposited from Cu(acac)2 and Cr(acac)3 precursors exhibit positive Hall co-efficient with the highest carrier Hall mobility reported to date for any p-type transparent conducting oxide based on Cu-delafossite structure. The deposition, performed at 823 K, grows at a rate of 13 nm min–1. XRD analysis indicates diffraction peaks corresponding to the (101), (012), (104), and (110) planes. The direct optical bandgap is calculated to be 3.08 eV.

    5. Structure and Unusual Substitution Reaction of Oligoether-Appended β-Diketonato Strotium Complex (pages 241–244)

      Y.-S. Min, Y.J. Cho, J.-H. Lee, D. Kim, I. Yoon, K.-M. Park, S.S. Lee and B.R. Cho

      Article first published online: 23 OCT 2003 | DOI: 10.1002/cvde.200304152

      The structure of a potential strontium MOCVD precursor is studied. Sr(methd)2 [methd = 1-(2-methoxyethoxy)-2,2,6,6-tetramethyl-3,5-heptadionate], an oligoether-appended strontium complex is shown to be a dimer in solution and liquid state. However, the complex is converted to another dimer during crystallization. A plausible equilibrium mechanism for this reaction is proposed (see Figure).

    6. Atomic Layer Deposition of Ta2O5 Using the TaI5 and O2 Precursor Combination (pages 245–248)

      J. Sundqvist, H. Högberg and A. Hårsta

      Article first published online: 23 OCT 2003 | DOI: 10.1002/cvde.200306243

      Polycrystalline films of tantalum oxide are deposited on Si(100) by atomic layer deposition employing TaI5 and O2 precursors. Growth studies in the temperature range of 400 to 700 °C indicate orthorhombic β-Ta2O5 films of good thickness uniformity which are iodine-free above 450 °C. Generally speaking the growth rate is found to be strongly dependent on the deposition temperature and reaches a maximum of 0.17 nm cycle–1 at 600 °C with a narrow temperature window for a temperature-independent growth. The process is optimized to obtain self-limiting growth and a straightforward thickness control.

    7. Growth Per Cycle in Atomic Layer Deposition: A Theoretical Model (pages 249–257)

      R.L. Puurunen

      Article first published online: 23 OCT 2003 | DOI: 10.1002/cvde.200306265

      A mathematical model is derived to relate the growth per cycle in ALD to precursor size and the chemisorption reactions involved. Steric hindrance by the adsorbed ligands, which typically restricts the growth to less than a monolayer per cycle, and the limited availability of bonding sites (see Figure) are identified as the growth-limiting saturation mechanisms.

    8. Substrate-Independent Palladium Atomic Layer Deposition (pages 258–264)

      J.J. Senkevich, F. Tang, D. Rogers, J.T. Drotar, C. Jezewski, W.A. Lanford, G.-C. Wang and T.-M. Lu

      Article first published online: 23 OCT 2003 | DOI: 10.1002/cvde.200306246

      A novel method is presented which allows the ALD of palladium onto dielectric surfaces. This is achieved by activating the dielectric surface with sulfide terminated silanes followed by the deposition of a palladium seed layer with the sequential pulsing of PdII(hfac)2 and glyoxylic acid above 200 °C; the acid acts as a novel remover to the chemisorbed organic ligand facilitating the deposition of the palladium seed layer. This is followed by palladium ALD with sequential pulsing of PdII(hfac)2 and H2 at a low temperature of 80 °C. The method is suggested to be appropriate to all metals that sublime and can chemisorb on the substrate without decomposition.

    9. Growth and Properties of TiCl4-Derived CVD Titanium Oxide Films at Different CO2/H2 Inputs (pages 265–271)

      D.-H. Kuo and C.-N. Shueh

      Article first published online: 23 OCT 2003 | DOI: 10.1002/cvde.200306245

      Crystalline titanium oxide films are deposited from TiCl4, CO2 and H2. Increasing deposition temperature and CO2/H2 ratio increases the O/Ti ratio in the deposited films and produces nanosized microstructures due to growth retardation. Two growth mechanisms are proposed to explain the tensile and compressive stresses in the CVD films (see Figure).

    10. Theoretical Investigation of the Gas-Phase Decomposition of Ga(N3)2Et as a Model for a Single-Molecule GaN Precursor (pages 272–278)

      B. Wolbank and R. Schmid

      Article first published online: 23 OCT 2003 | DOI: 10.1002/cvde.200306255

      Possible decomposition pathways of the gallium azide Ga(N3)2Et are investigated. The azide which serves as a model for the working precursor Ga(N3)2[(CH2)3NMe2] is studied using density functional theory type calculations taking into consideration both the kinetics and the thermodynamics of radical and non-radical reactions, focusing especially on the entropic effects at elevated temperatures. The β-hydrogen elimination is found to be kinetically favoured over the elimination of molecular nitrogen. A two step radical decomposition mechanism leading to the monoazide, GaN3, is proposed, which is consistent with the available experimental results.

    11. Pulsed Injection MOCVD of YSZ Thin Films onto Dense and Porous Substrates (pages 279–284)

      G. Garcia, J. Caro, J. Santiso, J.A. Pardo, A. Figueras and A. Abrutis

      Article first published online: 23 OCT 2003 | DOI: 10.1002/cvde.200306253

      YSZ layers are prepared on dense and porous substrates using pulse injection MOCVD. In this technique the precursors Zr(tmhd)4 and Y(tmhd)3 are evaporated from their solution microdroplets. The droplet characteristics of volume, precursor concentration, and injection frequency are studied in order to control the growth rate and microstructure of the layers and to determine the optimum parameters to achieve a dense microstructure of YSZ on dense substrates (see Figure).