Skip to main content
Article
Modeling crosshatch surface morphology in growing mismatched layers. Part II: Periodic boundary conditions and dislocation groups
Journal of Applied Physcis (2004)
  • A. M. Andrews, University of California, Santa Barbara
  • Richard Alan Lesar, University of California, Santa Barbara
  • M. A. Kerner, University of California, Santa Barbara
  • J. S. Speck, University of California, Santa Barbara
  • A. E. Romanov
  • A. L. Kolesnikova
  • M. Bobeth
  • W. Pompe
Abstract
We present further developments and understanding of the commonly observed crosshatch surface morphology in strain-relaxed heteroepitaxialfilms. We have previously proposed that the crosshatch morphology is directly related with strain relaxation via threading dislocation glide which results in both surface step and misfit dislocation (MD) formation [see Andrews et al., J. Appl. Phys. 91, 1933 (2002)—now referred to as Part I]. In this article, we have used solutions for the stress fields and displacement fields for periodic MD arrays which include the effects of the free surface. These solutions avoid truncation errors associated with finite dislocation arrays that were used in Part I. We have calculated the surface height profile for relaxed films where the misfit dislocations were introduced randomly or the misfit dislocations were placed in groups with alternating sign of the normal component of their Burgers vector. We have calculated the surface height profiles where the slip step remains at the surface [“slip step only” (SSO)] and where the slip step is eliminated [“slip step eliminated” (SSE)] due to annihilation of opposite sense steps, such as could happen during growth or lateral mass transport. For relaxed films, we find that the surface height undulations, characteristic of crosshatch, increase with increasing film thickness for the SSO case, whereas the surface becomes flatter for the SSE case. Experiments on relaxed In0.25Ga0.75Asfilms on (001) GaAs show that the surface height undulations in the [110] direction increase with increasing film thickness. Thus, we conclude that with increasing film thickness the crosshatch in the slow diffusion [110] direction is best described by the SSO case.
Publication Date
June 1, 2004
Publisher Statement
Copyright 2004 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
Citation Information
A. M. Andrews, Richard Alan Lesar, M. A. Kerner, J. S. Speck, et al.. "Modeling crosshatch surface morphology in growing mismatched layers. Part II: Periodic boundary conditions and dislocation groups" Journal of Applied Physcis Vol. 95 Iss. 11 (2004)
Available at: http://works.bepress.com/richard_lesar/7/