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

Journal Article · Mon May 30 04:00:00 EDT 2016 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4953095· OSTI ID:22590738

Zhigunov, D. M. ^[1]; Sarikov, A. ^[2]; Chesnokov, Yu. M.; Vasiliev, A. L. ^[3]; Zakharov, N. ^[4]; Kashkarov, P. K. ^[1]

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1. Faculty of Physics, M. V. Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow (Russian Federation)
2. IMDEA Materials Institute, c/ Eric Kandel, 2, 28906 Getafe, Madrid (Spain)
3. National Research Centre “Kurchatov Institute”, pl. Akademika Kurchatova 1, 123182 Moscow (Russian Federation)
4. 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, Journal Name: Applied Physics Letters Journal Issue: 22 Vol. 108; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANNEALING
FREE ENTHALPY
LAYERS
NANOSTRUCTURES
SILICON OXIDES
SUPERLATTICES
TEMPERATURE RANGE 1000-4000 K
THICKNESS
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY