ENHANCED EPITAXIAL-GROWTH ON SUBSTRATES MODIFIED BY ION SPUTTERING - GE ON GAAS(110)

The growth morphology of Ge on GaAs(110) has been modified by using io n sputtering at elevated temperatures to create GaAs vacancy islands p rior to Ge deposition. Scanning tunneling microscopy studies of growth on such surfaces show that the Ge nucleation density is increased sig nificantly and that this leads to island coalescence and uniform film formation at lower coverages than observed on unsputtered substrates. The driving force for this change in morphology is the reduction in en ergy achieved by saturation of dangling bonds at vacancy island steps. Vacancy islands with lateral sizes less than 100 Angstrom are most ef fective for such a growth.