Continuum field model of defect-induced heterogeneities in a strained thin layer

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We investigate the effect of external stresses on structural and mechanical properties of a strained damaged thin layer by developing a continuum phase-field mesoscale model based on the introduction of an order parameter field, the defect concentration, coupled with a displacement field. We find that even in the case of an initially uniform distribution of point defects external stresses drive the nucleation of local regions with higher concentration of vacancies or self-interstitials than their average value over the film. The effect can explain our experimental findings relating generation of highly heterogeneous regions in cobalt disilicide film fabricated in self-aligned processing on a silicon surface as well as improvement of fracture toughness in a tetragonal zirconia ceramics with oxygen vacancies.