Kinetic growth manipulation of Si(001) homoepitaxy

We have confirmed in a combined diffraction and STM study that the usual kinetic growth manipulation (KGM) applied to Si/Si(001) (nucleation at relatively low temperatures and completion of monolayer growth at high temperatures) does not lead to a smooth growth front. We have identified the physical reason for this unexpected behaviour: an anti phase boundary (APB) network develops during growth, due to the 2 x 1 reconstruction of the clean Si(001) surface. The density of this APB network can be substantially reduced by application of a different and optimised KGM procedure. Following a recipe in which 1 ML of Si on Si(001) is deposited at a relatively low temperature (525 K), followed by a short anneal to 750 K, results in a surface flatness similar to that of the clean Si(001) 2 x 1 surface. Up to 10 ML of material deposited with a flash anneal after the deposition of each additional layer resulted in a surface with a negligible reduction of the in-phase and out-of-phase intensity of a reflected low energy electron beam, indicative of an almost perfectly smooth growth front. STM images support this observation. The low thermal budget of this method reduces intermixing effects in hetero-epitaxial growth of group IV semiconductor (001)-faces. (C) 2004 Elsevier B.V. All rights reserved.