Crystal orientations and defect structures of GaAs layers grown on misoriented Si substrates by molecular-beam epitaxy

Abstract

The GaAs crystal orientations and the defect structures of the GaAs grown on misoriented (100) Si substrates have been investigated using chemical etching and transmission electron microscopy techniques. It was found that the GaAs orientations were uniquely determined on the (100) Si substrates tilted toward a (011) zone, and the GaAs layers were free from the antiphase domain problem. The reason was ascribed to the misoriented Si surface states, which consist of two-atom steps and preferentially aligned dangling bonds relative to the Si tilt direction. Also it was found that stacking faults and twins formed on the step terraces and propagated along only two out of four (111) planes. Most of them were annihilated near the GaAs/Si interface by crossing each other.