Selective-area epitaxial growth of gallium arsenide on silicon substrates patterned using a scanning tunneling microscope operating in air

Selective-area epitaxial growth of gallium arsenide on n-Si(100) substrates is reported, where the oxide (SiO_x) mask consists of 1-2 monolayer-thick features patterned onto a silicon substrate using a scanning tunneling microscope (STM) operating in air. The technique for generating the STM patterns on hydrogen-passivated silicon was reported recently [J. A. Dagata, J. Schneir, H. H. Harary, C. J. Evans, M. T. Postek, and J. Bennett, Appl. Phys. Lett. 56, 2001 (1990)]. The GaAs epilayer was grown by migration-enhanced epitaxy at 580 °C and its morphology was investigated by scanning electron microscopy. The chemical selectivity of the STM-patterned regions was verified by imaging time-of-flight secondary-ion mass spectrometry. The implications of these results for the development of a unique, STM-based nanostructure fabrication technology are discussed.