On the etching of silica and mesoporous silica films determined by X-ray reflectivity and atomic force microscopy

• Published in: Thin solid films 2009-03, Vol.517 (9), p.3028-3035
• Main Authors: Minhao, Y., Henderson, Mark J., Gibaud, A.
• Format: Article
• Language: English
• Subjects: Atomic force microscopy; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Etching; Exact sciences and technology; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials science; Mesoporous; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film; Thin film structure and morphology; X-ray reflectivity
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2008.12.017

X-ray reflectometry and atomic force microscopy were used to characterize the etching effect of 0.1 mol dm − 3 NaOH solution on mesoporous silica films < 100 nm thick produced by the evaporation induced self assembly route using a nonionic triblock co-polymer as the template. The effect of this treatment on films that had been partly condensed at 80 °C or fired at 400 °C in air are compared to non-porous films produced using conventional sol–gel technique. The evolution of film structure was monitored by atomic force microscopy and X-ray reflectometry. Thicknesses obtained from these measurements were used as an order parameter to determine the etch rate. For the mesoporous films, distinct stages corresponding to (a) film compression; (b) removal of the weakly organised caplayer; (c) progressive removal of bilayers of pores/silicated layres; and finally film collapse were revealed.