Nanoscale strain analysis of Si/Ge heterostructures

We report the quantitative characterization of strain components in semiconductor heterostructures of silicon-germaniums (Si
_0.76
Ge
_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
_xy
of interfaces and defects were mapped, respectively. The strain was about 3% in the interface region.