The structural properties of straight screw dislocations extended in the [001] direction formed in squared-and line shaped-Ge(001) films selectively grown on submicron regions of Si(001) substrates were investigated by transmission electron microscopy. The screw dislocations propagating as a result of spiral surface growth were redirected toward the SiO2 sidewalls. This redirection is linked to the formation of facets such as {111} facets in the growing Ge films. In the process of strain relaxation upon annealing, the screw dislocations were dissociated into dislocations with Burgers vectors of the a/2 < 110 > type, which glided on the {111} surfaces and disappeared. (C) 2011 Elsevier B.V. All rights reserved.