ATOMIC ORDERING AND DOMAIN-STRUCTURES IN METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION GROWN INGAAS (001) LAYERS

Transmission electron microscope, transmission electron diffraction, and high resolution electron microscope studies have been made of metal organic chemical vapor deposition In0.53Ga0.47As layers grown on (001) InP or GaAs substrates to investigate the CuPt-type atomic ordering and associated microstructures present. The amount of ordering, the geometry of the (111BAR) and (111BAR) ordered domains, and the occurrence of anti-phase boundaries (APBs) were determined as a function of the layer growth temperature and rate. The results are interpreted in terms of mechanisms involving ordering at the layer surface and disordering in a transition region below the surface. From a consideration of the former it is concluded that atomic steps associated with surface undulations have a major influence on the domain geometry and APBs. The different structures that occur, their dependence on growth conditions and their possible effects on the electrical and optical properties are discussed.