Ordered growth of germanium dots induced by the strain field of tilt dislocations in molecular bonded silicon (0 0 1) thin films

Abstract

Germanium dots have been grown on high twist angle (twist angle as high as 20°) molecular bonded silicon (0 0 1) substrates. We show that, depending on the thickness of the silicon film, the strain field generated by an ordered array of mixed edge interfacial tilt (miss-cut) dislocations may induce an ordered growth of germanium dots. We also show that in order to observe an influence of the mixed edge interfacial dislocations on the growth of germanium dots, the thickness of the film has to be much lower that the period of the mixed edge dislocations array. Germanium dots grown by molecular beam epitaxy on 10–15 nm thick silicon films with the period of tilt dislocation array of 43 nm show a high degree of self-ordering.