Tensile stress effect on indium diffusion in silicon substrate: Ab-initio study

초록

In this paper, we present our ab-initio study on energy configurations, minimum energy path (MEP), and migration energy for neutral indium diffusion in a uniaxial and biaxial tensile strained {100} silicon layer. Our ab-initio calculation of the electronic structure allowed us to figure out transient atomistic configurations during the indium diffusion in strained silicon. We found that the lowest-energy structure (Ins - Sii) consists of indium sitting on a substitutional site while stabilizing a silicon self-interstitial in a nearby tetrahedral position. Our ab-initio calculation also revealed that the next lowest energy structure is Ini, the interstitial indium at the tetrahedral position. We employed the nudged elastic band (NEB) method for estimating the MEP between the two structural states. The NEB method implies that the diffusion pathway of neutral indium is kept unchanged while the migration energy of indium fluctuates in strained silicon.