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Proceedings Paper

Optical properties of crystalline Al203 thin films grown by atomic layer deposition
Author(s): Jaan Aarik; Aarne Kasikov; Marco Kirm; Sven Lange; Teet Uustare; Hugo Mändar
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Paper Abstract

Atomic layer deposition of Al203 thin films on Si and Si02 substrates was investigated in the temperature range of 470- 1030 K. The films grown at 870-1030 K contained crystalline phase while those deposited at temperatures below 870 K were amorphous. The growth rate was 0.03 nm per cycle at 1030 K but it increased with decreasing temperature and reached 0.13 nm per cycle at 470 K. The densities of crystalline films were 3660-3670 kg/m3 while those of amorphous films ranged from 2820 to 3140 kg/m3. The refractive indices of crystalline films (1.75-1.77 at the wavelength of 500 nm) were significantly higher than the refractive indices of amorphous films. A disadvantage of crystalline films compared with amorphous films was somewhat higher surface roughness. Nevertheless, the extinction coefficient of the former films did not exceed 0.004 at the wavelength of 500 nm. Excitation of crystalline films at the wavelengths shorter than 175 nm resulted in a broadband photoluminescence peaking at 350-360 nm. The excitation spectrum indicated dominant excitation of this emission via interband transition. The intrinsic absorption edges of 7.2 and 6.6 eV were estimated for crystalline and amorphous films, respectively, from the long-wavelength edges of the excitation spectra measured at 10 K.

Paper Details

Date Published: 12 June 2006
PDF: 10 pages
Proc. SPIE 5946, Optical Materials and Applications, 594601 (12 June 2006); doi: 10.1117/12.639047
Show Author Affiliations
Jaan Aarik, Univ. of Tartu (Estonia)
Aarne Kasikov, Univ. of Tartu (Estonia)
Marco Kirm, Univ. of Tartu (Estonia)
Sven Lange, Univ. of Tartu (Estonia)
Teet Uustare, Univ. of Tartu (Estonia)
Hugo Mändar, Univ. of Tartu (Estonia)


Published in SPIE Proceedings Vol. 5946:
Optical Materials and Applications

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