Atomic layer deposition of Cr2O3 thin films:: Effect of crystallization on growth and properties

Atomic layer deposition of Cr(2)O(3) thin films from CrO(2)Cl(2) and CH(3)OH on amorphous SiO(2) and crystalline Si(1 0 0) and alpha-Al(2)O(3)(1 (a) over bar 0 2) substrates was investigated, and properties of the films were ascertained. Self-limited growth with a rate of 0.05-0.1 nm/cycle was obtained at substrate temperatures of 330-420 degrees C. In this temperature range epitaxial eskolaite was formed on the alpha-Al(2)O(3)(1 (1) over bar 0 2) substrates. The predominant crystallographic orientation in the epitaxial films depended, however, on the growth temperature and film thickness. Sufficiently thick films grown on the SiO(2) and Si(1 0 0) substrates contained also the eskolaite phase, but thinner films deposited at 330-375 degrees C on these substrates were amorphous. The growth rate data of films with different phase composition allowed a conclusion that the crystalline phase grew markedly faster than the amorphous phase did. The amorphous, polycrystalline and epitaxial films had densities of 4.9, 5.1 and 5.1-5.3 g/cm(3), respectively. (C) 2008 Elsevier B.V. All rights reserved.