Raman scattering characterization of residual strain and alloy composition in bulk Si_1−xGe_x crystal

¹ Division of Information and Production Science, Graduate School of Engineering and Science, Kyoto Institute of Technology, Matsugasaki Sakyo-ku, Kyoto 606-8585, Japan
² Department of Electronics and Information Science, Kyoto Institute of Technology, Matsugasaki Sakyo-ku, Kyoto 606-8585, Japan
³ Institute of Crystal Growth, Max-Born-Straβe 2, D-12489 Berlin, Germany
⁴ Advanced Materials R & D Laboratories, Sumitomo Electric Industries Ltd., 1-1-1 Koya-kita, Itami, Hyogo 664, Japan

Corresponding author: islam@djedu.kit.ac.jp

Received: 18 July 2003
Accepted: 13 February 2004
Published online: 15 July 2004

Abstract

Raman scattering (RS) experiments have been carried out to determine both residual strain and alloy composition in a bulk Si_1−xGe_x single crystal with compositional gradient, which can be used as a focusing and diffracting X-ray monochromator. Since RS results are influenced both by strain and by composition, it is difficult to determine them separately from the observed phonon position. By analyzing strain effect on RS in connection with a strain model developed for bulk mixed crystals, both residual strain and alloy composition are evaluated. It is found that the alloy composition evaluated from the RS results is in good agreement with that measured by the standard chemical analysis. It is also found that the axial and radial strain components vary from −0.76×10⁻³ to −1.2×10⁻³ and 3.6×10⁻⁴ to 5.7×10⁻⁴, respectively, for the almost linear variation in composition from 0.034 to 0.055.