Improvement of the surface morphology of the epitaxial γ-Al2O3 films on Si(111) grown using template growth with different temperatures by Al solid and N2O gas source molecular beam epitaxy (MBE)

We have investigated the crystalline quality and surface morphology of gamma-Al2O3 films to make clear growth mode of Al2O3 grown by Al solid and N2O gas source MBE, and proposed a template growth method with different growth temperatures. The single-crystalline epitaxial Al2O3 layers were successfully grown at growth temperatures between 650 and 900 degrees C. However, at the higher temperatures above 800 degrees C, the surface morphology of films was very rough because of the etching of Si substrates by N2O gas in the initial growth stage of Al2O3 growth. The Al2O3 films grown at low temperatures below 650 degrees C were polycrystalline due to SiO2 formed in the initial growth stage. The Al2O3 films grown with a template growth method have a lower values of RMS than that of Al2O3 films grown by usual growth method for same film thickness. (C) 1999 Elsevier Science B.V. All rights reserved.