ION-BEAM ENHANCED EPITAXIAL-GROWTH OF GE (001)

An enhancement in surface smoothness during molecular beam epitaxial growth of Ge on Ge (001) by 200 eV Xe ion bombardment has been measured with reflection high-energy electron diffraction. We show that the steady-state surface is smoother during simultaneous ion bombardment and growth at 400°C than during ion bombardment or growth alone. The smoothest surface is obtained when the rate of deposition is approximately equal to the rate of production of ion-induced surface defects. It is suggested that the smoothening is the consequence of the ion-induced vacancy-like defects annihilating with surface atoms and/or destabilizing small clusters.