Estimation of Asymmetrically Distributed Anti-phase Domains Ratio in GaAs/Si(100) Epitaxial Layers Using High Resolution X-Ray Diffraction

Anti-phase domains (APD) deteriorate the electronic and optical properties of the polar layer grown on non-polar substrates. It is important to estimate the relative population of the APD in the grown layer such that the growth parameters can be tuned to obtain APD free epilayer for better optoelectronic properties. The strain energy relaxation of the APD rich layer is found to be more complex in nature than the strain energy relaxation of APD free layer. The initial relaxation in the APD rich layers occurs along orthogonal directions whereas in APD free layer initial relaxation occurs along a particular in-plane direction. In this article, a method is proposed to estimate the APD ratio in (100) epitaxy case for polar layer grown on a non-polar substrate by measuring the values of lateral coherence length with the help of high-resolution X-ray diffraction technique. The proposed method is applicable to any polar layer grown on (100) oriented non-polar substrate and is independent of the substrate miscut.