Zusammenfassung
An experimental facility for carrying out x-ray multiple diffraction
(XRMD) studies in parallel-beam geometry using the Daresbury synchrotron
radiation source and its application in the study of coherency of an
epilayered sample are described. Experimental high-resolution Renninger
scans (RS) about GaAs(006) are presented and the pseudoforbidden
`'Aufhellung'' eight-beam (000,006,020,042,044,026,<0(2)over
bar4>,<0(2)over bar2>) case has been fully resolved for the first time
using the setup which involves a double-crystal six-circle scattering
geometry and data acquisition providing optimal conditions for these
scans to be obtained. A sample of InGaAs/AlGaInAs/InP (001) epilayered
material was also examined and high-resolution RS from the bulk,
substrate, and epitaxial overlayers were obtained. The diffraction
wavelength used was determined directly from the bulk RS as lambda=(1.4695+/-0.0005) Angstrom. The data clearly reveal a number of
interesting XRMD features which allow for the sample characterization.
The layer parallel lattice parameter can be determined either from the
epilayer tetragonal distortion in the layer RS or from the MORSI
(modulation of the RS intensity due to the presence of the epilayers)
Greenberg & Ladell, Appl. Phys. Lett. 50, 436 (1987) dips in the
substrate RS. These dips can also provide simultaneous information on
relative tilt and rotation between both layer/substrate lattices. The
fitting of the position and profile of the three-beam surface peaks
allows the determination of the layer parallel lattice parameter and the
layer mosaic spread on the sample surface plane. (C) 1996 American
Institute of Physics.
Nutzer