MOLECULAR-BEAM EPITAXIAL-GROWTH OF INAS ON A (311)A CORRUGATED SURFACE - GROWTH-MECHANISM AND MORPHOLOGY

Kinetic molecular beam epitaxy growth processes and the structure of t he InAs (311)A surface were investigated in situ by reflection high en ergy electron diffraction (RHEED) and ex situ by low energy electron d iffraction (LEED) and scanning tunneling microscopy (STM). Two stable surface structures, (2X15) and (1x5), were observed by RHEED on as-gro wn surfaces. RHEED oscillations have a strong azimuthal anisotropy wit h maximum amplitude in the [(2) over bar 33] direction and minimum amp litude in the [01 (1) over bar] direction, suggesting that this surfac e grows via propagation and coalescence of pronounced two dimensional nuclei along the [(2) over bar 33] azimuth. Ex situ LEED and STM studi es of the As-capped InAs (311)A surfaces confirmed the strong anisotro py of the surface structure. A characteristic feature of the LEED patt erns is the degeneration of the principal diffraction into streaks alo ng the [01 (1) over bar] direction. STM images show rows running along the [(2) over bar 33] direction. Although the spacing between the row s varies, there are local areas showing lateral periodicities of simil ar to 2.15 nm [(1X5) structure] and similar to 6.45 nm [(2X15) structu re] along the [01 (1) over bar] direction, consistent with RHEED obser vations. (C) 1998 American Vacuum Society.