Determination of lattice parameters of SiGe/Si(110) heterostructures

We have investigated the crystal structures of SiGe layers grown on Si(110) substrates. A method was developed to analyze Ge composition and strain parameters along [1¯10] and [001] directions, considering anisotropic in-plane strain relaxation process. Samples grown by solid source molecular beam epitaxy (MBE) showed that strain in SiGe layers preferentially relaxed along [1¯10] direction. However, the samples grown by gas source MBE showed formation of domains that had different lattice orientations. Result of the analysis showed that the domains tilted towards [001]/[001¯] directions, by 0.4–0.6°. It was found that the crystal structure strongly depends on growth conditions and sample structures.