Accurate determination of misfit strain, layer thickness, and critical layer thickness in ultrathin buried strained InGaAs/GaAs layer by x-ray diffraction

Abstract

We have analyzed data obtained from double-crystal x-ray rocking curve measurements to determine the lattice constants, strain relaxation, thickness, and critical thickness of a thin InxGa1−xAs layer embedded in GaAs. The use of a very wide x-ray scan angle (∼2.0°) allows the simultaneous determination of buried layer thickness and strain with greater accuracy. The critical thicknesses so obtained for buried InGaAs layers are smaller than that predicted by the energy balance model and larger than that predicted by the force balance model.