The effects of step bunching on a CuPt-B ordered structure in Ga0.5In0.5P grown on (11n) B and (11n) A (n=8, 13) GaAs substrates by metalorganic vapor phase epitaxy (MOVPE) are described. In the GaInP layers, a CuPt-B ordered structure in the [111] B and [111] B directions are formed. The epitaxial growth surfaces are often undulated due to the atomic-step bunching. Experimental results for a low V/III ratio of 55 shows that a disordered region of the CuPt-B or-dered structure is formed at the step-bunched surface. Also, anti-phase domain boundaries of the CuPt-B ordered structure are formed on terraced surfaces for V/III ratio of 1500. The ordered structure domain formation is thought to depend on the growth on surface facets which are formed through P-dimer distribution there.
