A thermodynamic formalism was developed for the predominant point defect mechanism of self-diffusion and impurity diffusion in Si. It was used to provide a rigorous basis for the point-defect based interpretation of diffusion results for biaxially strained epitaxial layers in the present system. It was found that a certain combination of the hydrostatic and biaxial stress dependences of the diffusivity was equal to ±1 times the atomic volume; depending upon whether the predominant mechanism involved vacancies or interstitials. Experimental results for Sb diffusion in biaxially strained Si-Ge films, and first-principles calculations of the activation volume for Sb diffusion via a vacancy mechanism, were shown to be quantitative agreement (with no free parameters).

M.J.Aziz: Applied Physics Letters, 1997, 70[21], 2810-2