Chemical Vapor Deposition

Cover image for Chemical Vapor Deposition

March, 2003

Volume 9, Issue 2

Pages 55–110

    1. Contents: Chem. Vap. Deposition 2/2003 (pages 55–56)

      Version of Record online: 20 MAR 2003 | DOI: 10.1002/cvde.200390002

    2. Chemical Vapor Infiltration of Rhenium (pages 59–63)

      H.C. King, M.C. Renier, K.E. Ellzey and W.J. Lackey

      Version of Record online: 20 MAR 2003 | DOI: 10.1002/cvde.200390003

      The chemical vapor infiltration (CVI) of rhenium is investigated by the pyrolytic decomposition of ReCl5 prepared both by the chlorination of rhenium metal (see Figure) and the sublimation of ReCl5. The feasibility of the CVI of rhenium is demonstrated for both methods. Statistical analyses shows that the amount of rhenium deposited increases for higher chlorine flow rates and lower preform temperatures, 750 vs 900°C, for the chlorination and sublimation processes, respectively.

    3. Structure and Thermal Properties of Thin Film Poly(α-methylstyrene) Deposited via Plasma-Enhanced Chemical Vapor Deposition (pages 65–71)

      D.D. Burkey and K.K. Gleason

      Version of Record online: 20 MAR 2003 | DOI: 10.1002/cvde.200390004

      PECVD from α-methylstyrene is a dry method for synthesizing directly patternable sacrificial materials for generating pores or air dielectric layers. Deposition is studied under continuous and pulsed plasma-enhanced CVD conditions. Effects of plasma power and aging on the structure and thermal stability of the films are studied by FTIR, solid-state NMR and thermal stability analysis. Increasing plasma excitation power is found to change the structure of the deposited films to an increasingly cross-linked structure. This allows some tailoring of the films to be achieved.

    4. A Kinetic Model for Step Coverage by Atomic Layer Deposition in Narrow Holes or Trenches (pages 73–78)

      R.G. Gordon, D. Hausmann, E. Kim and J. Shepard

      Version of Record online: 20 MAR 2003 | DOI: 10.1002/cvde.200390005

      Highly conformal coatings inside holes and trenches with very high aspect ratios are achieved using complementary self-limiting reaction of suitable pairs of reactants supplied in alternating doses. A theory is developed and a simple formula is derived for the required exposure time. The theory is in total agreement with data gathered from the reaction of hafnium dimethylamide and water vapor to form hafnium oxide films that are completely conformal in holes with an aspect ratio of 43 (see Figure).

    5. Chemical Vapor Deposition of TixSi1–xO2 Films: Precursor Chemistry Impacts Films Composition (pages 79–86)

      R.C. Smith, N. Hoilien, C. Dykstra, S.A. Campbell, J.T. Roberts and W.L. Gladfelter

      Version of Record online: 20 MAR 2003 | DOI: 10.1002/cvde.200390006

      Thin films of TixSi1–xO2 are deposited on Si(100) at 300 to 535°C by LPCVD using TEOS (tetraethyl orthosilicate) and either TTIP (titanium tetra isopropoxide) or TN (anhydrous titanium(IV) nitrate). Deposited films are shown to be amorphous with TiO2/SiO2 ratio dependent on the choice of titanium precursor. In the TN–TEOS system, the titanium content remains close to 50% for all conditions studied. However, in the TTIP–TEOS system, systematic variation of titanium content with deposition conditions can be explained by a growth scenario that limits SiO2 growth to TiO2 sites within the composite film.

    6. The Metal–Organic Chemical Vapor Deposition of Lanthanum Nickelate Electrodes for Use in Ferroelectric Devices (pages 87–92)

      P.A. Lane, M.J. Crosbie, P.J. Wright, P.P. Donohue, P.J. Hirst, C.L. Reeves, C.J. Anthony, J.C. Jones, M.A. Todd and D.J. Williams

      Version of Record online: 20 MAR 2003 | DOI: 10.1002/cvde.200390007

      Lanthanum nickelate (LNO) films are deposited on Si/SiO2 and sapphire substrates at 630 °C by liquid delivery MOCVD using La(thd)3 and Ni(thd)2 (thd = 2,2,6,6-tetramethyl-3,5-heptadionato) dissolved in tetrahydrofuran and heptane. The as grown layers are highly crystalline (see Figure) and highly oriented on Si/SiO2 substrates. Electrical resistivity is found to be dependent on La:Ni ratio, substrate and annealing conditions with a minimum value of 300 μΩ cm for LNO on (0001) sapphire.

    7. Single-Source Chemical Vapor Deposition of Zinc Sulfide-Based Thin Films from Zinc bis(O-ethylxanthate) (pages 93–98)

      D. Barreca, E. Tondello, D. Lydon, T.R. Spalding and M. Fabrizio

      Version of Record online: 20 MAR 2003 | DOI: 10.1002/cvde.200390008

      A novel single source precursor is investigated to deposit ZnS-based films. Depositions are carried out on SiO2 and SiO2/Si substrates in a cold-wall CVD reactor at 250 to 400°C using zinc bis(O-ethylxanthate). Atomic force microscopy analysis indicates that the surface morphology is influenced more by the substrate type than growth temperature. Surface and in-depth chemical composition analyses carried out using X-ray photoelectron spectroscopy, secondary ion mass spectrometry, and X-ray excited Auger electron spectroscopy reveal the presence of zinc oxides also. Optical measurements indicate that the transparency of deposited films is higher than 80% throughout the visible and IR ranges.

    8. Deposition of Compositionally Graded Mullite/Alumina Coatings from Mixtures of SiCl4, AlCl3, CO2 and H2 (pages 99–104)

      S.F. Nitodas and S.V. Sotirchos

      Version of Record online: 20 MAR 2003 | DOI: 10.1002/cvde.200390009

      A two-stage process is developed to prepare compositionally graded mullite (3Al2O3·2 2SiO2) and alumina (Al2O3) coatings by CVD (Figure), from mixtures of SiCl4, AlCl3, CO2 and H2. Firstly the deposit composition is changed from almost stoichiometric mullite to that of a deposit with high alumina content by increasing flow, and thus reducing residence time. Then the mole fraction of SiCl4 is gradually reduced to zero, producing an outer layer of alumina.

    9. Effects of an Added Iodine Source (C2H5I) on Ru Metal–Organic Chemical Vapor Deposition (pages 105–109)

      J.J. Kim, M.S. Kim and D.Y. Yoon

      Version of Record online: 20 MAR 2003 | DOI: 10.1002/cvde.200390000

      The effects of ethyl iodide (C2H5I) as an iodine source are investigated for Ru films grown on TiN/Ti/Si wafers by MOCVD using Ru-(EtCp)2 as a precursor. Although the introduction of the additional step of adsorbing C2H5I during the deposition is found not to affect the orientation of the ruthenium films deposited, the resistivity of films thinner than 40nm decreases by 20% or less. Moreover the introduction of iodine extends the surface-reaction-limited regime of the deposition to 400 °C on account of which an increased deposition rate and improved film properties can be expected.