Affiliations: Research Institute for Networks & Communications
Engineering (RINCE), Dublin City University, Dublin 9, Ireland | Engineering Materials Department, University of
Southampton, Highfield, Southampton SO17 1BJ, United Kingdom | Optoelectronics Laboratory, Helsinki University of
Technology, PO Box 3000, 02015 TKK, Finland | D-79108, Freiburg, Germany
Note: [] Correspondence address: Dr. Patrick J. McNally, Microelectronics
Laboratory, Research Institute for Networks & Communications Engineering
(RINCE), Dublin City University, Dublin 9, Ireland. Tel.: +353 1 7045119; Fax:
+353 1 7045508; E-mail: mcnallyp@eeng.dcu.ie
Abstract: Synchrotron X-Ray Topography has been used in Total Reflection
Topography (TRT) mode to observe strain induced surface bumps due to the
presence of underlying misfit dislocations in strained layer SiGe on Si
epitaxial heterostructures. In these experiments the x-rays approached the
sample surfaces at grazing incident angles below the total external reflection
critical angles for a number of reflections and hence surface strain features
nominally less than a few tens of Ångstroms from the sample surface have
been observed. These are similar to the surface bumpiness observed by Atomic
Force Microscopy, albeit on a much larger lateral length scale. The fact that
TRT mode images were taken was confirmed by the observation of clear and
conventional back reflection topographic images of misfit dislocations in all
samples when the grazing incidence angle became greater than the critical
angle.
Keywords: x-ray topography, total reflection, SiGe, misfit dislocations, epitaxy, strain
