Chemical Vapor Deposition

Cover image for Chemical Vapor Deposition

August, 2004

Volume 10, Issue 4

Pages 183–238

    1. Silicon Doping of Gallium Nitride Using Ditertiarybutylsilane (pages 187–190)

      C.J. Deatcher, C. Liu, M.-G. Cheong, L.M. Smith, S. Rushworth, A. Widdowson and I.M. Watson

      Version of Record online: 8 SEP 2004 | DOI: 10.1002/cvde.200304171

      Ditertiarybutylsilane is demonstrated as an effective silicon n-dopant source for GaN. The air-stable liquid silicon source is shown to offer significant safety advantages over the hydride gases in current use. Transport measurements using the Hall technique, supplemented by high-resolution XRD and AFM (Figure), have been used to confirm that the quality of GaN doped using this precursor is very similar to that currently doped by SiH4. Free carrier concentrations between 8 × 1016 and 7 × 1018 are achieved.

    2. Self-Limited Pore Size Reduction of Mesoporous Silica Membranes via Pyridine-Catalyzed Silicon Dioxide ALD (pages 190–194)

      B.A. McCool and W.J. DeSisto

      Version of Record online: 8 SEP 2004 | DOI: 10.1002/cvde.200304172

      The pore size of mesoporous silica membranes is reduced using pyridine-catalyzed SiO2 ALD within the mesoporous matrix. The use of pyridine to catalyze the ALD results in lowering the reaction temperature to 80 °C. It also self-limits the pore size reduction as shown in gas permeation experiments. The self-limiting aspect of the deposition, controlled by size exclusion of catalyst from the pore, has the potential of controlling the pore size within the membrane. The paper concludes that this technique may prove useful as a general technique for healing defects in membranes.

    3. Combinatorial CVD of Zirconium, Hafnium, and Tin Oxide Mixtures for Applications as High-κ Materials (pages 195–200)

      B. Xia, F. Chen, S.A. Campbell, J.T. Roberts and W.L. Gladfelter

      Version of Record online: 8 SEP 2004 | DOI: 10.1002/cvde.200306287

      Continuous compositional spreads of ZrO2/HfO2/SnO2 are created on Si(100) wafers (Figure) using a modified LPCVD reactor. The deposition is carried out using anhydrous metal nitrates as precursors and the composition of the deposit is determined using RBS. An array of capacitors used to map the dielectric constant (κ) of the deposited spread show that films having high ZrO2 concentrations possess high dielectric constants, while high SnO2 concentrations correlates with low values of (κ).

    4. Atomic Layer Deposition of ZrO2 Thin Films Using Dichlorobis[bis-(trimethylsilyl)amido]zirconium and Water (pages 201–205)

      W.-H. Nam and S.-W. Rhee

      Version of Record online: 8 SEP 2004 | DOI: 10.1002/cvde.200306277

      A novel zirconium precursor for ALD of ZrO2 is introduced. The ALD characteristics of zirconia on Si using dichlorobis[bis(trimethylsilyl)amido]zirconium and water are studied as a function of deposition temperature. The film growth shows self-limiting characteristics with maximum growth of 1.6 Å cycle–1 achieved at 175 °C. The composition of the as-deposited amorphous films are analyzed by RBS, XPS, and SIMS, and the amount of Si in ZrO2 films is found to be in the range of 1.1– 5.4 at.-%. On rapid annealing in Ar at 700–900 °C, the deposited films are crystallized, mainly in the cubic phase, with no significant change in surface morphology.

    5. Facile Synthesis and Characterization of New β-Diketonate Silver Complexes. Single-Crystal Structures of (1,1,1,5,5,5-Hexafluoro-2,4-pentadionato)(2,2′-bipyridine)silver(I) and (1,1,1,5,5,5-Hexafluoro-2,4-pentadionato)(N,N,N′,N′-tetramethylethylenediamine)silver(I) and Their Use as MOCVD Precursors for Silver Films (pages 207–213)

      L. Zanotto, F. Benetollo, M. Natali, G. Rossetto, P. Zanella, S. Kaciulis and A. Mezzi

      Version of Record online: 8 SEP 2004 | DOI: 10.1002/cvde.200306290

      Two new air-stable β-diketonate Ag(I) complexes are synthesized. The two compounds [Ag(hfac)(bipy)]2 and [Ag-(hfac)(tmeda)]n (Figure) are prepared using a simple procedure and their suitability as Ag MOCVD precursors is examined. The thin silver films obtained from the deposition appear to be of good quality and analyses of the as-deposited films using XRD, XPS, and AFM indicate that the second compound is a more promising MOCVD precursor for the deposition of Ag films.

    6. Atomic Layer Deposition of Ruthenium Thin Films from Ru(thd)3 and Oxygen (pages 215–219)

      T. Aaltonen, M. Ritala, K. Arstila, J. Keinonen and M. Leskelä

      Version of Record online: 8 SEP 2004 | DOI: 10.1002/cvde.200306288

      Ruthenium films are grown from [Ru(thd)3] by ALD and oxygen. Films deposited in the temperature range 325–450 °C are reported to be polycrystalline metallic ruthenium of good adherence and a preferred (002) orientation. Growth rate of 0.36 Å cycle–1 at 350 °C and film resistivities below 20 μΩ cm are reported. Impurity contents of the films (< 2.9 at.-% H, < 1.9 at.-% C, and < 5.5 at.-% O) are found to be nearly independent on the precursor pulse time as analyzed by TOF-ERDA. However, films grown from Ru(thd)3 are found to have lower growth rate and longer induction times than films grown from RuCp2.

    7. A Simple Index to Restrain Abnormal Protrusions in Films Fabricated Using CVD under Diffusion-Limited Conditions (pages 221–228)

      Y. Kajikawa, S. Noda and H. Komiyama

      Version of Record online: 8 SEP 2004 | DOI: 10.1002/cvde.200306285

      Cauliflower-like protrusions formed in CVD processes are studied both experimentally and theoretically. Both approaches indicate that the difference in diffusion fluxes to the film and to the protrusions (Figure) controls the growth of such protrusions. To simplify model protrusion growth, a 1D model is presented by hypothesizing the diffusion of growth species in the boundary layer above a growing film. By controlling the process conditions, protrusion free SiC films are successfully deposited from dichloromethylsilane.

    8. CVD of Nanophasic (Zn, Cd)S Thin Films: From Multi-Layers to Solid Solutions (pages 229–236)

      D. Barreca, A. Gasparotto, C. Maragno, E. Tondello and C. Sada

      Version of Record online: 8 SEP 2004 | DOI: 10.1002/cvde.200306292

      Nanostructured ZnxCd1–xS (0 ≤ x ≤ 1) thin films are synthesized on SiO2 substrates using M(O-iPrXan)2 (M = Zn, Cd; O-iPrXan = S2COCH-(CH3)2) as precursors in a sequential deposition of single-phase MS coatings at 300 °C in N2 followed by ex-situ annealing in an inert atmosphere at different temperatures. Annealing at 600 °C for 3 h results in the formation of a homogeneous ZnxCd1–xS solid solution while annealing at higher temperatures results in induced CdS sublimation. The interrelation between film properties and processing conditions are investigated, focusing in particular on the (Zn,Cd)S evolution to ZnxCd1–xS solid solutions.