Single crystal erbium oxide films up to 150 nm thick were grown directly on Si (1 1 1) substrates by molecular beam epitaxy (MBE). The formation of erbium silicide interfacial phases was successfully suppressed by control over critical growth parameters. Wafers were characterized by in situ optical reflectometry and post-growth X-ray diffraction, ellipsometry, photoluminescence mapping and electron microscopy. By correlating these results we have established MBE growth protocols such that silicide formation can be detected immediately during growth, thereby enabling a more production-oriented approach to growth of erbium oxide films. (c) 2008 Elsevier B.V. All rights reserved.