Abstract
High-quality single-crystal nanothick Y2 O3 films have been grown epitaxially on Si (111) despite a lattice mismatch of 2.4%. The films were electron beam evaporated from pure compacted powder Y2 O3 target in ultrahigh vacuum. Y2 O3 3 nm thick exhibited a bright, sharp, streaky reconstructed (4×4) reflection high energy electron diffraction pattern. Structural studies carried out by x-ray diffraction with synchrotron radiation and high-resolution transmission electron microscopy show that the films have the cubic bixbyite phase with a remarkably uniform thickness and high structural perfection. Two Y2 O3 domains of B -type Y2 O3 [2 1- 1-] Si [11 2-] and A -type Y2 O3 [2 1- 1-] Si [2 1- 1-] coexist in the initial film growth with B type predominating over A type in thicker films as studied using x-ray diffraction. The narrow full width at half maximum of 0.014° in the ω -rocking curve is the characteristic of excellent crystalline films. High-resolution transmission electron microscopy and fast Fourier transform analysis show atomically sharp interface and strain relaxation in thicker films. © 2008 American Vacuum Society.