Atomistic modelling for boron diffusion in strained silicon substrate

Abstract

We discuss the issue of boron diffusion in biaxial tensile strained {001} Si and SiGe layer with kinetic Monte Carlo (KMC) method. We created strain in silicon by artificially adding a germanium mole fraction to the silicon in order to perform a theoretical analysis. The strain energy of the charged defects was calculated from ab initio calculation whereas the diffusivity of boron was extracted from the Arrhenius formula. Hereby, the influence of the germanium content on the diffusivity of the impurity atom was estimated. Our KMC study revealed that the diffusion of the boron atoms was retarded with increasing germanium mole fraction in the strained silicon layer. Furthermore, we derived the functional dependence of the in-plane strain as well as the out-of-plane strain as a function of the germanium mole fraction, which is based on the distribution of equivalent stress along the Si/SiGe interface.