X-ray diffraction analysis for step and linearly graded InxGa1−xAs/GaAs (001) heterostructures using various hkl reflections

Abstract

In this paper, the authors present dynamical x-ray rocking curves for step and linearly graded InxGa1−xAs/GaAs (001) heterostructures containing dislocations. The x-ray rocking curve analysis for a number of reflection profiles including 002, 004, 006, 044, 135, 335, 444, and 117 was conducted assuming Cu kα1 radiation. The analysis provides an accurate estimation for the threading dislocation density in step graded structures from the broadening of the individual rocking curve peaks. The rocking curve has little sensitivity to the threading dislocation density for linearly graded InxGa1−xAs/GaAs (001) buffer layers regardless of the hkl reflection which is chosen, but the dislocation density for a uniform layer on top of a linearly graded buffer may be estimated from its rocking curve width.