Thickness and temperature depending intermixing of SiO{sub x}/SiO{sub 2} and SiO{sub x}N{sub y}/SiO{sub 2} superlattices: Experimental observation and thermodynamic modeling
- Faculty of Physics, M. V. Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow (Russian Federation)
- IMDEA Materials Institute, c/ Eric Kandel, 2, 28906 Getafe, Madrid (Spain)
- National Research Centre “Kurchatov Institute”, pl. Akademika Kurchatova 1, 123182 Moscow (Russian Federation)
- Max-Planck-Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Germany)
Multilayered SiO{sub x}/SiO{sub 2} and SiO{sub x}N{sub y}/SiO{sub 2} thin films were fabricated using different techniques and subsequently annealed at high temperatures (≥1100 °C) in order to form Si nanocrystals by means of the well-known superlattice approach. The thickness of the SiO{sub x} and SiO{sub x}N{sub y} layers was varied from 1.5 to 5 nm, while for the SiO{sub 2} layers it was fixed at 4 nm. Using transmission electron microscopy, we showed that the multilayered structure generally sustains the high temperature annealing for both types of films. However, for samples with ultrathin SiO{sub x} or SiO{sub x}N{sub y} layers a breakdown of the superlattice structure and a complete intermixing of layers were observed at high temperatures. On the contrary, annealing at lower temperature (900 °C) preserves the multilayered structure even of such samples. Theoretical calculations showed that the intermixing of SiO{sub x}/SiO{sub 2} and SiO{sub x}N{sub y}/SiO{sub 2} superlattices in the ultrathin layers thickness limit may be explained thermodynamically by the gain in the Gibbs free energy, which depends in turn on the annealing temperature.
- OSTI ID:
- 22590738
- Journal Information:
- Applied Physics Letters, Vol. 108, Issue 22; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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