TEMPERATURE-DEPENDENT UNSTABLE HOMOEPITAXY ON VICINAL GAAS(110) SURFACES

The surface morphology of GaAs thin films grown by molecular beam epit axy on (110) substrates misoriented towards (111)A is studied using at omic force microscopy in a wide range of growth temperatures. Two regi mes of unstable growth with distinct growth morphologies are identifie d. Al substrate temperatures between 450 and 500 degrees C, macrosteps are created with step edges oriented along [110] or [1 (1) over bar 2 ]. Above 550 degrees C, GaAs(IIO) vicinal surfaces become unstable tow ards transverse meandering, and a ripple pattern morphology with ridge s running along the [001] direction is formed. We attribute the two ty pes of growth instabilities observed to differences in attachment kine tics of adatoms to surface steps at different As surface coverages. (C ) 1998 Elsevier Science B.V. All rights reserved.