Measurement and simulation of boron diffusion in strained Si1-xGex epitaxial layers with a linearly graded germanium profile

The diffusion of boron in compressively strained Si1-xGex epitaxial layers with graded Ge profiles grown by rapid pressure chemical vapor deposition d uring furnace and rapid thermal annealing has been studied. Comparison of t he Si(1-x)G(x) samples to Si samples after furnace annealing (FA) and rapid thermal annealing (RTA) revealed a retarded B diffusion inside the straine d Si1-xGex layer. FA after RTA has only a marginal effect on B diffusion. T he extracted B diffusivity from the present studies is very well comparable with available experimental and simulation results. A simple empirical exp ression for B diffusion is presented and incorporated into a diffusion mode l for dopants in heterostructures. Good agreement between the measured and simulated diffusivity is observed. It is argued that B diffusion in straine d Si1-xGex layers requires the inclusion of both trapping effect and strain in the formulation of the diffusion mechanism. (C) 2001 Elsevier Science L td. All rights reserved.