Multiscale modeling of stress-mediated diffusion in silicon: Ab initio to continuum

In this letter, we present the development of a complete methodology to sim ulate the effects of general anisotropic nonuniform stress on dopant diffus ion in silicon. The macroscopic diffusion equation is derived from microsco pic transition-state theory; the microscopic parameters are calculated from first principles; a feature-scale stress-prediction methodology based on s tress measurements in the relevant materials as a function of temperature h as been developed. The developed methodology, implemented in a continuum so lver, is used to investigate a TiN metal gate system. A compressive stress field is predicted in the substrate, resulting in an enhancement in lateral boron diffusion. This enhancement, which our model attributes mostly to so lubility effects, is in good agreement with experiment. (C) 2001 American I nstitute of Physics.