title: Strain evolution in coherent Ge/Si islands
abstract: Strain evolution of coherent Ge islands on Si(001) is measured using a newly developed transmission electron microscopy technique based on two-beam dark-field strain imaging. The strain measurements show that a metastable Ge island shape is involved in the shape transition between pyramids and domes; this shape is more readily observed for growth at 550 than 600 degrees C because of the slower rate at which islands cross the kinetic barrier between shapes. The strain relaxation changes discontinuously between pyramids and domes, indicating that the underlying shape transition is first order.
authors.affiliation: Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 South Goodwin Avenue, Urbana, Illinois 61801, USA.
authors.initials: CP
authors.lastname: Liu
authors.initials: JM
authors.lastname: Gibson
authors.initials: DG
authors.lastname: Cahill
authors.initials: TI
authors.lastname: Kamins
authors.initials: DP
authors.lastname: Basile
authors.initials: RS
authors.lastname: Williams