Atomic hydrogen cleaning of GaAs(001): a scanning tunnelling microscopy study

Reflection high-energy electron diffraction and scanning tunnelling microscopy have been used to study the cleaning of the native oxide from an epi-ready GaAs(001) substrate using thermally cracked atomic hydrogen (AH). Cleaning at 400 degreesC results in the formation of a (2 x 4) reconstructed As-terminated surface. A short anneal (5 min) under an As-2 flux at 600 degreesC produces an atomically smooth surface, which is comparable in quality to that obtained after conventional substrate preparation by thermal oxide removal and prolonged homoepitaxial buffer growth. Our results show that AH cleaning is a very effective method for preparing clean GaAs(001) surfaces for use in an epitaxial growth environment without any further treatment. (C) 2003 Elsevier B.V. All rights reserved