Misfit dislocation formation has been controlled during growth at 500-
degrees-C in strained, 720 nm Si0.90Ge0.10 on Si. The Si substrates we
re selectively Ge+ ion implanted and etched to form a series of mesas
with stripes of implant damaged crystal. Misfit dislocations nucleated
preferentially from the ion implanted regions during epitaxial layer
growth, while other nucleation sources were inhibited by the low growt
h temperature and the etched trenches between mesas. Films were relaxe
d by as much as 35%. The epitaxial layers on some mesas were relaxed i
n essentially one [110] direction as well. Electron beam induced curre
nt images indicate that ion-implant activated misfit dislocations form
before heterogeneous nucleation sources can operate, so that relaxati
on occurs in a more uniform manner.