Structural properties of In0.53Ga0.47As epitaxial films grown on Si (111) substrates by molecular beam epitaxy

In0.53Ga0.47As epitaxial films are grown on 2-inch diameter Si (111) substrates by growing a low-temperature In0.4Ga0.6As buffer layer using molecular beam epitaxy. The effect of the buffer layer thickness on the as-grown In0.53Ga0.47As films is characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy and transmission electron microscopy (TEM). It is revealed that the crystalline quality and surface morphology of as-grown In0.53Ga0.47As epilayer are strongly affected by the thickness of the In0.4Ga0.6As buffer layer. From TEM investigation, we understand that the type and the distribution of dislocations of the buffer layer and the as-grown In0.53Ga0.47As film are different. We have demonstrated that the In0.4Ga0.6As buffer layer with a thickness of 12 nm can advantageously release the lattice mismatch stress between the In0.53Ga0.47As and Si substrate, ultimately leading to a high-quality In0.53Ga0.47As epitaxial film with low surface roughness.