Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials
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Influence of thermal annealing on the structure and optical properties of thin aluminum nitride films on sapphire

O.V. Devitskiy1,2, A.A. Kravtsov1,2, A.S. Pashchenko1, I.A. Sysoev2

1 Federal Research Center Southern Scientific Center of the Russian Academy of Sciences
2 North Caucasus Federal University

DOI: 10.26456/pcascnn/2020.12.591

Original article

Abstract: The results of an experimental study of the effect of thermal annealing on the structure, surface morphology and optical properties of thin films of aluminum nitride on sapphire are presented. Thin films of aluminum nitride on sapphire with a thickness of 200 nm were annealed in air and in a nitrogen atmosphere at a residual gas pressure in the vacuum chamber of the ion-beam deposition unit of no less than 100 Pa at a temperature of 850 °C. It was found that thermal annealing of aluminum nitride films on sapphire in a nitrogen atmosphere leads to a decrease in the root mean square roughness of the films to 0,8 nm, an increase in the transmittance in the wavelength range of 300 ‑ 1100 nm up to 96 %, and an increase in the stoichiometry of the films. It is shown that for aluminum nitride films annealed in air on sapphire, aluminum nitride is oxidized to form amorphous aluminum oxide at a temperature of 850 °C. The results of energy dispersive analysis showed the complete absence of nitrogen on the surface of these films. A decrease in the transmittance over the entire wavelength range for films AlN annealed in air makes them unsuitable for use in optoelectronics. The surface morphology of these films is an array of pointed formations with a maximum height 190,7 nm and an arithmetic mean surface roughness 3,7 nm.

Keywords: aluminum nitride, ion-beam deposition, thermal annealing, nanoheterostructures, sapphire, optical properties, energy dispersive analysis

  • Oleg V. Devitskiy – Ph. D., Senior Researcher, Laboratory of Physics and Technology of Semiconductor Nanoheterostructures for Microwave Electronics and Photonics Federal Research Center Southern Scientific Center of the Russian Academy of Sciences, Senior Researcher, Scientific and Educational Center for Photovoltaics and Nanotechnology North Caucasus Federal University
  • Aleksandr A. Kravtsov – Ph. D., Senior Researcher, Laboratory of Physics and Technology of Semiconductor Nanoheterostructures for Microwave Electronics and Photonics Federal Research Center Southern Scientific Center of the Russian Academy of Sciences, Researcher, Scientific and Educational Center for Photovoltaics and Nanotechnology North Caucasus Federal University
  • Alexander S. Pashchenko – Ph. D. in Physics and Mathematics, Leading Researcher of the Laboratory of Physics and Technology of Semiconductor Nanoheterostructures for Microwave Electronics and Photonics Federal Research Center Southern Scientific Center of the Russian Academy of Sciences
  • Igor A. Sysoev – Dr. Sc., Docent, Director of the Scientific and Educational Center for Photovoltaics and Nanotechnology North Caucasus Federal University

Reference:

Devitskiy, O.V. Influence of thermal annealing on the structure and optical properties of thin aluminum nitride films on sapphire / O.V. Devitskiy, A.A. Kravtsov, A.S. Pashchenko, I.A. Sysoev // Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials. – Tver: TSU, 2020. — I. 12. — P. 591-600. DOI: 10.26456/pcascnn/2020.12.591. (In Russian).

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