Atomistic calculation of elastic moduli in strained silicon

Strained silicon is becoming a new technology in silicon industry where the novel strain-induced features are utilized. In this paper we present a molecular dynamic prediction for the elastic stiffnesses C₁₁, C ₁₂ and C₄₄ in strained silicon as functions of the volumetric strain level. Our approach combines basic continuum mechanics with the classical molecular dynamic approach, supplemented with the Stillinger-Weber potential. Using our approach, the bulk modulus, effective elastic stiffnesses C₁₁, C₁₂ and C₄₄ of the strained silicon, including also the effective Young's modulus and Poisson's ratio, are all calculated and presented in terms of figures and formulae. In general, our simulation indicates that the bulk moduli, C₁₁ and C₁₂, increase with increasing volumetric strain whilst C₄₄ is almost independent of the volumetric strain. The difference between strained moduli and those at zero strain can be very large, and therefore use of standard free-strained moduli should be cautious. © 2006 IOP Publishing Ltd.