Temperature evolution of defects and atomic ordering in Si1−xGex islands on Si(001)

Abstract

Articles you may be interested in Persistent monolayer-scale chemical ordering in Si1−xGex heteroepitaxial films during surface roughening and strain relaxation J. Appl. Phys. 118, 245302 (2015); 10.1063/1.4938475Influence of composition and substrate miscut on the evolution of {105}-terminated in-plane Si1−xGex quantum wires on Si (001 The observation of atomic ordering and signatures of defects in self-assembled Ge islands using x-ray diffraction techniques have been previously treated as unrelated subjects. However, mutual understanding can be achieved when both subjects are studied in a common frame. Here, we report on measurements and analysis of both defects and atomic ordering in Si 1Àx Ge x islands epitaxially grown on Si(001) substrates as a function of growth temperature. By using x-ray diffraction and mapping around a bulk forbidden reflection, defect sizes, and in-plane spacing between nearby dislocations are extracted and related to the composition of the islands. The results fit well with an independent determination using selective wet chemical etching and atomic force microscopy measurements. Moreover, the temperature dependence of the ordered domain size is discussed. Although both atomic ordering and defect formation take place independently in the system, it is found that the relaxation provided by the onset of defects does not affect the formation of ordered domains, recently pointed out to be stabilized by strain and surface equilibrium on islands facets.

Surface Morphology Transformation Under High-Temperature Annealing of Ge Layers Deposited on Si(100)

“…Annealing can also produce significant changes in the surface morphology [ 16 ]. The temperature effects were studied with respect to compositional atomic ordering and surface morphology evolution for the SiGe islands prepared by the deposition of relatively low Ge coverages (up to several nm) [ 17 , 18 ]. In the first part of this work, we study the surface morphology obtained by the deposition of relatively high Ge coverages (30–150 nm) on Si(100) at temperatures of 400–500 °C.…”