
Figure 1
Models of partly relaxed epitaxial Ge(001) layers on Si(001) substrates. (a) Crystal lattices of a relaxed Ge(001) layer on an Si(001) substrate. (b) Conventional relations of a Ge(001) epitaxial layer on Si(001). a^{S} and c^{S} are the lattice constants of the bottom Si(001) layer. a^{L,R} and c^{L,R} are the relaxed lattice constants of the top Ge(001) layer. a^{L} and c^{L} are the actual or strained lattice constants of the top Ge(001) layer. (c) Coincidencesite lattices of a Ge(001) epitaxial layer on Si(001). Axes X and Y correspond to sample basis axes S_{1} and S_{2}. Relaxation vectors R_{1} and R_{2} have directions and of the sample principal basis and length values corresponding to relaxation degree. Gray circles mark out coinciding pairs of lattice nodes  anchors A^{1}{Ge[110]; Si[110]}, A^{2}{Ge[]; Si[]}. (d) Demonstration of anisotropic relaxation of an epitaxial layer. Relaxation vectors R_{1} and R_{2} show the directions of relaxation and strain degree. 