(Color online) Imaging XRT conditions from diffracting planes in epitaxial layer (light-colored) and substrate (dark).
(Color online) Geometry of a 224 reciprocal space map. In the asymmetrical configuration the scattering vector q () has two components qz and qx.
XRT image of a section of sample A100 showing precipitate (probably SiO2) contrast within the substrate. No dislocations from the 100 nm thick SiGe layer are visible.
XRT image of a section of sample A200. Typical straight misfit dislocation contrast in both 〈110〉 directions is visible. The 〈110〉 directions are the intersections of the (001) interface with the (111) glide planes.
XRT image of a section of sample A400. Multiple dislocation generation and overlap of dislocations from different sources happens frequently.
(Color online) XRT image of a section of sample A800. The high density dislocation network cannot be resolved with XRT. But the grainy structure indicates variable strain levels probably caused by the inhomogeneous dislocation nucleation.
(Color online) (004) scans of samples A100, A200, A400, reported in q z units.
(Color online) 224 RSM of sample A200. The axis are in hkl units. Si Bragg peak is located at h = k = 2 and l = 4, while the SiGe one appears at lower l value (strain).
Geometry of a parallel set of misfit dislocations along [ ]. The orthogonal dislocation set is not shown to avoid overload of the drawing. The dislocation spacing is given by the distance p. The Burger’s vector b, and its projection length b′ on the interface normal to the dislocations are shown for the (111) glide plane
(Color online) 224 RSM of sample A800. The axis are in hkl units. Si Bragg peak is located at h = k = 2 and l = 4, while the SiGe one appears at lower l and h values (larger lattice parameters).
The relative force of a strained layer (1−r) · t vs thickness (logt). Increase of the force up to the upper bound t co then sudden decrease at the relaxation branch. The force causes a curvature of the wafer.
Experimental (crosses) relative strain values (1−r) vs thickness (logt). The strain is nearly constant up to an upper bound t co where strong relaxation sets in.
Relaxation r vs thickness t. The early stage of heterogeneous nucleation is represented by a straight line the extrapolation of which to r = 0 gives the lower bound t cl of the critical thickness band.
Ge contents x (from (004) XRD, (224) and (115) RSM), thicknesses t SiGe from XRD fringes (except A800, which gives the nominal value as fringes are only visible in unrelaxed layers) and relaxation r (from XRT and RSM).
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