Study of Al2O3 nanolayers synthesized onto porous SiO2 using X-ray reflection spectroscopy

• Published in: Thin solid films 2013-05, Vol.534, p.363-366
• Main Authors: Konashuk, A.S., Sokolov, A.A., Drozd, V.E., Schaefers, F., Filatova, E.O.
• Format: Article
• Language: English
• Subjects: Alumina; L2,3-near edge absorption structure; Low-k dielectrics; Porous silica; Thin films; X-ray reflection spectroscopy
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2013.03.020

The structure of alumina (Al2O3) films with different thickness grown by the atomic layer deposition method on porous silica substrates has been studied using soft X-ray reflection spectroscopy. It was established that synthesized films were amorphous and the proportion of Al coordination (tetrahedral: octahedral) depends on the film thickness. The film growth starts from excess of tetrahedral (AlO4) coordination and thickening of the film leads to increasing of number of octahedral (AlO6) coordination in the structure. A critical thickness of amorphous Al2O3 film exists (in the range of studied films, this is a thickness of 13nm). For thicker films, the structure of amorphous Al2O3 film corresponds to massive film with the typical proportion of tetrahedrally and octahedrally coordinated sites in the structure. •Growth of Al2O3 film on porous SiO2 begins with excess of AlO4 coordinations.•On the contrary, film growth on nonporous substrates starts with excess of AlO6.•When thickness reaches 13nm, the film achieves structure of massive amorphous Al2O3.•Substrate material doesn't affect structure for thicknesses more than 13nm.