AVS 50th International Symposium
    Electronic Materials and Devices Wednesday Sessions
       Session EM-WeM

Paper EM-WeM7
Displacive Phase Transition in SrTiO@sub 3@ Thin Films Grown on Si(001)

Wednesday, November 5, 2003, 10:20 am, Room 321/322

Session: Multifunctional Electronic Materials
Presenter: F.S. Aguirre-Tostado, CINVESTAV-Querétaro, México
Authors: F.S. Aguirre-Tostado, CINVESTAV-Querétaro, México
A. Herrera-Gómez, CINVESTAV-Querétaro, México
J.C. Woicik, National Institute of Standards and Technology
R. Droopad, Motorola
Z. Yu, Motorola
D.G. Schlom, Pennsylvania State University
J. Karapetrova, University of Illinois and Argonne National Lab
P. Zschack, University of Illinois and Argonne National Lab
P. Pianetta, Stanford Synchrotron Radiation Laboratory
Correspondent: Click to Email
Polarization dependent x-ray absorption fine structure and x-ray diffraction have been used to study the local structure in SrTiO@sub 3@ thin films grown epitaxially on Si(001). For films less than a critical thickness of ~ 80 Å, a splitting of the Ti-O distance perpendicular to the interface is observed: r@sub Ti-O@ = 1.87 ± 0.02 Å and r@sub Ti-O@ = 2.09 ± 0.06 Å, whereas only a single Ti-O distance is observed within the plane of the interface: r@sub Ti-O@ = 1.95 ± 0.01 Å. These findings indicate that the in-plane compressive strain imposed on the SrTiO@sub 3@ layer by the Si substrate results in a tetragonal plus displacive ferroelectric distortion of the SrTiO@sub 3@ cubic unit cell. This study therefore suggests the existence of a Curie "thickness" for strained-layer, epitaxial perovskite growth.