Nanoscale strain analysis of Si/Ge heterostructures

We report the quantitative characterization of strain components in semiconductor heterostructures of silicon-germaniums (Si_0.76Ge_0.24) grown on Si substrate with an inserted Ge layer by an ultrahigh vacuum chemical vapor deposition system. Strain analysis was performed using a combination of high-resolution transmission electron microscopy and geometric phase analysis. The numerical moire method was applied to visualize the lattice fringe surrounding the defects. The strain components epsiv_xx, epsiv_yy, epsiv_xyof interfaces and defects were mapped, respectively. The strain was about 3% in the interface region.