The 2×1/1×2 surface reconstruction of a homoepitaxial diamond (001) surface has been examined using a scanning tunneling microscope at an atomic scale and reflection electron microscopy at a macroscopic scale. The monohydride dimer, which is a unit of the surface reconstruction, has a symmetric structure. These monohydride structures contribute to the surface p-type conduction in undoped films. The surface is composed of elongated dimer rows. Antiphase boundaries have been observed, which is indicative of low-temperature epitaxy where surface migration is limited. Macroscopic surface flatness has been improved during the growth stage in the presence of oxygen and boron which enhance migration.

• Received 13 June 1995

DOI:https://doi.org/10.1103/PhysRevB.52.11351