X-ray double-crystal analysis of misorientation and strain in GaAs/Si and related heterostructures

This is the authors' abstract. We don't add key points for this paper.

A detailed x-ray double-crystal-diffractometry investigation of GaAs on Si tilted towards [110] direction has been carried out to understand the structure, misorientation, and residual stress present in this system. The structure of the GaAs epilayer is approximately triclinic, with the in-plane lattice parameters a and b being in most cases slightly larger than, and that along the growth direction c less than, the bulk GaAs. For vicinal angles between 0° and 5°, a tilt angle of up to 0.12° between GaAs and Si lattice is observed, inclined mostly in the same direction as the vicinal angle, but also having a small component in a perpendicular direction. A residual tensile stress of the order of 109 dyn/cm2 exists in the epilayer, which can be accounted for by the difference in the thermal expansion coefficients of GaAs and Si. The strain due to the lattice parameter mismatch between the two materials is found to be negligibly small.