Pinholes, Dislocations and Strain Relaxation in InGaN
B. Jahnen, M. Albrecht, W. Dorsch, S. Christiansen, H. P. Strunk
Institut für Werkstoffwissenschaften, Lehrstuhl VII, Universität Erlangen-Nürnberg
D. Hanser, Robert F. Davis
Department of Materials Science and Engineering, North Carolina State University
This article was received on Friday, July 17, 1998 and
accepted on Monday, October 19, 1998. Abstract
We
analyse by means of transmission electron microscopy (TEM) and atomic force
microscopy (AFM) the strain relaxation mechanisms in InGaN layers on GaN as
dependent on the In content. At the experimentally given thickness of
100 nm, the layers remain coherently strained, up to an In concentration
of 14 %. We show that part of the strain is reduced elastically by
formation of hexagonally facetted pinholes. First misfit dislocations are
observed to form at pinholes that reach the InGaN/GaN interface. We discuss
these results in the framework of the Matthews-Blakeslee model for the critical
thickness considering the Peierls force for glide of threading dislocations in
the different slip systems of the wurtzite lattice.Outline
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Cite this article as: MRS Internet J. Nitride Semicond. Res. 3, 39(1998).
last updated Monday, October 19, 1998 1:09:59 PM.© 1998 The Materials Research Society
