Growth of Ge–Si(111) epitaxial layers: intermixing, strain relaxation and island formation

Influence of material, surface reconstruction, and strain on diffusion at the Ge(111) surface

“…In our experiment we used the known fact that on top of 3D Ge islands grown on Si͑111͒ a large flat area with a (7ϫ7) reconstruction exists. 12 On the one hand there are several indications that these 3D islands are largely relaxed. First, the Ge lattice spacing inside the 3D islands was measured by electron diffraction to be ϳ70% relaxed.…”

“…On a 2 ML thick Ge film both (5ϫ5) and (7ϫ7) surface reconstruction domains are found. 12 One could assume that the (7ϫ7)-reconstructed domain is intermixed with Si and maintains the (7ϫ7) structure due to a large Si content. If Si/Ge intermixing does occur in the 2 ML Ge film, one would expect that intermixing would be strongest for low deposition rates.…”

Controlling the quantum dot nucleation site

“…1b). The evolution of the WL in Ge/Si(111) was discussed recently [10], and it is shown in Fig. 2, starting at 0.65 ML up to 2 ML where the percolation threshold is attained.…”

Atomic description of elementary surface processes: diffusion and dynamics

“…The main questions to be pursued in this context are: how the strain leads to island formation, and the role of Ge-Si intermixing; both questions have been addressed in a series of recent papers [30][31][32][33][34][35]. Besides, it is not yet possible to grow islands of desired size, shape and density, partly because the experimental results available today are lacking detailed knowledge of the SK growth dynamics, particularly on the atomic scale.…”

“…When the Ge coverage exceeds 3 ML [32,33], several 3D islands appear at random locations on the surface. At the beginning they have a triangular shape (truncated triangular pyramids, or tetrahedra), average lateral dimensions 500-1000 A A and are about 1 ML high.…”