On the basis of non-equilibrium thermodynamics, a model for the transport processes and quasi-chemical reactions of particles in semiconductor crystals was developed, and a diffusion equation was derived for the case of impurity diffusion in the vicinity of a semiconductor interface. This took account of transport via the generation, migration and dissociation of so-called "impurity atom - intrinsic point defect" pairs. The drift of particles in an internal stress field which arose from the interfacial lattice mismatch of 2 neighboring semiconductors was taken into account by the equation. Other factors which were considered were: spatial non-uniformity of the point-defect distributions, the existence of various charge states of particles, the drift of charged particles under an internal electric field, and cluster formation. Simulations of In redistribution in the vicinity of In0.53Ga0.47As/In0.52Al0.48As heterojunction interfaces, and of O redistribution near to a polysilicon grain boundary during heat treatment were performed. A comparison with experimental data showed that the proposed model provided an explanation of up-hill diffusion and of other details of impurity redistribution around the interfaces of compound semiconductor heterojunctions and polysilicon grain boundaries.

O.I.Velichko, A.K.Fedotov: Solid State Phenomena, 1997, 57-58, 513-8