The diffusion of boron in strained Si(1-x)Gq(x) epitaxial layer has been studied using secondary ion mass spectroscopy (SIMS). We present a simplified diffusion model that includes the coupling reaction between Ge and B, which acts as a clustering center for the boron clusterisation process. This clustering model is efficient for the rapid thermal as well as furnace annealing conditions. We showed that the simulated and SIMS diffused profiles agree very well and the boron profile within strained Si1-xGex epitaxial layer is well confined. The inclusion and exclusion of Ge-B coupling reaction term R in the diffusion model are discussed more elaborately by comparing with SIMS data. (C) 2003 Elsevier Science Ltd. All rights reserved.