STEP STRUCTURES DURING MBE GROWTH OF GAAS AND ALGAAS FILMS ON VICINAL GAAS(110) SURFACES INCLINED TOWARD (111)B

We have investigated step structures during molecular beam epitaxial (MBE) growth of GaAs and AlGaAs films on vicinal GaAs(110) surfaces inclined at 6-degrees toward (111)B using reflection high-energy electron diffraction. We find that during AlGaAs growth at temperatures above 630-degrees-C, the surfaces contain regular arrays of steps with double-layer height. At temperatures below 610-degrees-C, the surface breaks up into two types of regions: one consisting of wide (110) facets without steps, the other consisting of arrays of steps with a high step density. During GaAs growth at temperatures above 580-degrees-C, all the surfaces contain well-ordered arrays of steps with double-layer height. Based on the results, we discuss the formation mechanism of the quantum well wire-like structures reported previously.