Preparation of Amorphous Al2O3 Thin Films from Stabilized Al-Alkoxides by the Sol-Gel Method

Abstract

Highly transparent amorphous thin films of Al₂O₃ were prepared by adding some chelating agents such as β-diketones to the Al-alkoxide/alcohol starting solutions. Among the β-diketones examined, ethylacetoacetate was the most effective in stabilizing the alkoxides against water, because of the formation of an Alchelate complex. The Al₂O₃ films obtained were amorphous and transparent below 700°C, whereas they crystallized in γ-Al₂O₃ at 900°C, which transformed to α-Al₂O₃ at 1000°C, accompanying the loss of transparency.