Development of low-temperature deposition processes by atomic layer epitaxy for binary and ternary oxide thin films

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Doctoral thesis (article-based)
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Date
2002-03-08
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Degree programme
Language
en
Pages
69, [68]
Series
Inorganic chemistry publication series / Helsinki University of Technology, 2
Abstract
Atomic layer epitaxy (ALE) method was employed for the study of growth of binary and ternary metal oxide thin films. As background for the study, the basic principles of the ALE method are presented together with a review of existing ALE deposition processes and precursors for oxide thin films. The suitability of β-diketonate type precursors (M(thd)3 M=Sc,Y,La; thd = 2,2,6,6-tetramethylheptanedione) and ozone were studied for ALE depositions of Group 3 oxides, namely Sc2O3, Y2O3 and La2O3. All three oxides could be deposited by a self-limiting ALE process once a suitable deposition temperature was identified. The optimal deposition temperature was found to depend on the position of the self-limiting deposition region, but also on the impurity content, which increases at low deposition temperatures. Deposition rate of Sc2O3 was considerably higher from organometallic precursor, (C5H5)3Sc, than from β-diketonate precursor (0.75 Å(cycle)-1 vs. (0.125 Å(cycle)-1). In a second set of experiments, the suitability of the ALE processes developed was tested for the deposition of ternary thin films, namely yttria-stabilised zirconia (YSZ) and lanthanum aluminate. Before these processes were applied, study was made of the deposition of ZrO2 from β-diketonate and organometallic precursors at 200-500 °C. Furthermore, ALE deposited MgO films were tested for their suitability as buffer layers between silicon substrate and LaAlO3 film. Crystalline YSZ films were obtained regardless of the yttrium to zirconium ratio, whereas the LaAlO3 films were crystalline only after annealing at 900 °C.
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Keywords
oxide thin films, atomic layer epitaxy, atomic layer deposition
Parts
  • Putkonen, M., Nieminen, M., Niinistö, J., Sajavaara, T. and Niinistö, L., Surface-controlled deposition of Sc<sub>2</sub>O<sub>3</sub> thin films by atomic layer epitaxy using β-diketonate and organometallic precursors, Chem. Mater. 13 (2001) 4701-4707.
  • Putkonen, M., Sajavaara, T., Johansson, L.-S. and Niinistö, L., Low temperature ALE deposition of Y<sub>2</sub>O<sub>3</sub> thin films from β-diketonate precursors, Chem. Vap. Deposition 7 (2001) 44-50.
  • Nieminen, M., Putkonen, M. and Niinistö, L., Formation and stability of lanthanum oxide thin films grown by atomic layer epitaxy, Appl. Surf. Sci. 174 (2001) 155-165.
  • Putkonen, M. and Niinistö, L., Zirconia thin films by atomic layer epitaxy. A comparative study on the use of novel precursors with ozone, J. Mater. Chem. 11 (2001) 3141-3147.
  • Putkonen, M., Sajavaara, T., Niinistö, J., Johansson, L.-S. and Niinistö. L., Deposition of yttria-stabilized zirconia thin films by atomic layer epitaxy from β-diketonate and organometallic precursors, J. Mater. Chem., in press.
  • Putkonen, M., Johansson, L.-S., Rauhala, E. and Niinistö, L., Surface-controlled growth of magnesium oxide thin films by atomic layer epitaxy, J. Mater. Chem. 9 (1999) 2449-2452.
  • Putkonen, M., Sajavaara, T. and Niinistö, L., Enhanced growth rate in atomic layer epitaxy deposition of magnesium oxide thin films, J. Mater. Chem. 10 (2000) 1857-1861.
  • Nieminen, M., Sajavaara, T., Rauhala, E., Putkonen, M. and Niinistö, L., Surface-controlled growth of LaAlO<sub>3</sub> thin films by atomic layer epitaxy, J. Mater. Chem. 11 (2001) 2340-2345.
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Permanent link to this item
https://urn.fi/urn:nbn:fi:tkk-001355