Atomic step organization in homoepitaxial growth on GaAs(111)B substrates

Journal Article · Fri Jul 01 04:00:00 EDT 1994 · Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena; (United States)

DOI:https://doi.org/10.1116/1.587805· OSTI ID:7247745

Schowalter, L J; Yang, K ^[1]; Thundat, T ^[2]

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1. Physics Department and Center for Integrated Electronics, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)
2. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

When homoepitaxial growth is performed on exactly oriented (singular)([bar 1][bar 1][bar 1]) GaAs substrates, while maintaining [radical]19[times][radical]19 surface reconstruction, the initially flat surface evolves vicinal ([bar 1][bar 1][bar 1]) facets tilted approximately 2.5[degree] toward [l angle]2[bar 1][bar 1][r angle] azimuthal directions. These facets form pyramidlike structures where distance between adjacent peaks can be varied from as little as 1[mu]m to 10's of [mu]m. Atomic force microscopy show that these surfaces are extremely smooth with the observed tilt resulting from atomic steps spaced at approximately 7.5 nm. We have also studied growth on vicinal GaAs([bar 1][bar 1][bar 1]) substrates. If the substrate surfaces are tilted 3[degree] toward the [2[bar 1][bar 1]] direction, then a very smooth surface is obtained with uniform spacing of atomic steps running along the [0[bar 1][bar 1]] direction. For vicinal substrates tilted 2[degree] or less toward the [2[bar 1][bar 1]] azimuth, the surface evolves a grating structure consisting of approximately singular ([bar 1][bar 1][bar 1]) facets and vicinal ([bar 1][bar 1][bar 1]) facets tilted approximately 2.5[degree] toward the [2[bar 1][bar 1]] azimuth. As the sizes of the singular ([bar 1][bar 1][bar 1]) facets are made larger (by growing on vicinal substrates with smaller misorientations), occasional inclined three-sided pyramids are observed with the three symmetric, vicinal ([bar 1][bar 1][bar 1]) facets. Vicinal substrates tilted along other directions are observed to form zigzag terraces that result from appropriate combinations of oriented and vicinal ([bar 1][bar 1][bar 1]) facets. Results are interpreted as indicating that the 2.5[degree] vicinal ([bar 1][bar 1][bar 1]) surface has a minimum free energy for the [radical]19[times][radical]19 reconstruction (i.e., that 10 nm spacing of [l angle]011[r angle] steps is thermodynamically preferred).

• OSTI ID: 7247745
• Journal Information: Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena; (United States), Journal Name: Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena; (United States) Vol. 12:4; ISSN 0734-211X; ISSN JVTBD9
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360601* -- Other Materials-- Preparation & Manufacture
ARSENIC COMPOUNDS
ARSENIDES
COHERENT SCATTERING
DIFFRACTION
ELECTRON DIFFRACTION
ENERGY
EPITAXY
FREE ENERGY
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
MICROSCOPY
MOLECULAR BEAM EPITAXY
MORPHOLOGY
PHYSICAL PROPERTIES
PNICTIDES
SCATTERING
SURFACE ENERGY
SURFACE PROPERTIES
THERMODYNAMIC PROPERTIES