In this work, the initial stage of the aluminium-induced layer-exchange (ALILE) process is studied theoretically. The diffusion of silicon atoms from an amorphous Si layer into an Al layer through a permeable membrane prior to Si grain nucleation within the Al layer is considered. A kinetic model is derived to describe this process. In the framework of this model, the evolution of the Si concentration within the Al layer prior to Si grain nucleation and the nucleation time are investigated for different annealing temperatures and preparation conditions of the membrane. From the comparison of results of calculations with experimental data, the pre-exponent factors and activation energies of diffusion coefficients of Si in membranes are determined. (c) 2005 Elsevier B.V. All rights reserved.