New kinetic growth instabilities in Si(001) homoepitaxy

We have conducted an atomic force microscopy (AFM) study of homoepitaxial s ilicon layers deposited on vicinal Si(001) substrates under frequently empl oyed molecular beam epitaxy (MBE) growth conditions. Samples with different miscut angles and miscut directions were overgrown with epilayers of thick nesses up to 7500 Angstrom and subsequently examined. A previously unknown kinetic growth instability results in distinct, highly regular surface morp hologies with a considerable height of up to 40 Angstrom and periods of up to 0.45 mu m. The surface morphological features can be associated with the intrinsic properties of the Si surface and show a strong sensitivity to th e growth temperature. With increasing layer thickness the morphology underg oes a simultaneous steepening and coarsening process. A qualitative model i s discussed to explain our experimental results. (C) 2000 Elsevier Science S.A. All rights reserved.