X-ray scattering study of lattice relaxation in ErAs epitaxial layers on GaAs

• Published in: Applied physics letters Vol. 58; no. 15; pp. 1602 - 1604
• Main Authors: MICELI, P. F, PALMSTRØM, C. J, MOYERS, K. W
• Format: Journal Article
• Language: English
• Published: Melville, NY American Institute of Physics 15-04-1991
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Physics; Structure of solids and liquids; crystallography; X-ray diffraction and scattering; Gallium Arsenides; X ray scattering; Lattice relaxation; Erbium Arsenides; Thin film; Dislocation
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.105138

We present the results of a high-resolution x-ray scattering study of the lattice relaxation in [001]ErAs epitaxial layers grown on [001]GaAs. Three thickness regimes are found. ErAs is pseudomorphic on GaAs for thicknesses below 70 Å and between 70 and 300 Å lattice relaxation is observed concomitant with an increase of the in-plane mosaic due to the formation of misfit dislocations. Above 300 Å, the out-of-plane transverse scattering from the ErAs lattice planes is no longer specular and further relaxation appears to be related to the out-of-plane mosaic. The ratio of elastic constants, C12/C11, is measured to be 0.126. Thin-film interference oscillations are observed and modeled, finding that for 140 Å of ErAs the interface fluctuations are ∼2.5 monolayers. ErAs/GaAs is an ideal system for x-ray scattering studies of lattice relaxation and structure in epitaxial layers.