Cubic-on-cubic growth of a MgO(001) thin film prepared on Si(001) substrate at low ambient pressure by the sputtering method

¹  Kanagawa Industrial Technology Center, Kanagawa Prefectural Government 705-1 Shimo-Imaizumi, Ebina, Kanagawa 243-0435, Japan
²  Department of Innovative and Engineered Materials, Tokyo Institute of Technology 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502 Japan

Received: 5 October 2007
Accepted: 4 December 2007

Abstract

Magnesium oxide (MgO) films were prepared on a Si(001) substrate by the rf sputter- ing method at low ambient pressure using a metal target. The X-ray diffraction verified the epi- taxial growth of MgO(001) with a cubic-on-cubic arrangement despite the large lattice mismatch between MgO(100) and Si(100), and contractions of the unit cell along both the out-of-plane and in-plane directions. Epitaxial growth is described as a domain epitaxial relation with a domain mismatch consisting of (k) lattice units of the Si substrate and (mn) ones of the MgO film. To visualize the domain mismatch with combinations of k, , m and n, coherent strains were depicted on polar coordinates. The domain mismatch was estimated as a small value, which was further decreased by the contraction of the unit cell in the epitaxial MgO film.