Thp organization of coherent three-dimensional islands during the grow
th of SiGe/Si multilayers on Si(100) was investigated with cross-secti
onal transmission electron microscopy. Merging of islands of different
initial size is found to be the dominant mechanism leading to a unifo
rm size distribution. Upon overgrowth with Si, we observe a change of
the shape of the islands from the {105}-faceted ''hut'' to a boxlike s
hape bounded on top by a (100) facet. (C) 1997 American Institute of P
hysics.