Interdiffusion in strained Si/strained SiGe epitaxial heterostructures

Abstract

The Si–Ge interdiffusivity in epitaxial strained Si/Si1−yGey/strained Si/relaxed Si1−x0Gex0 and strained Si/relaxed Si1−x0Gex0 heterostructures is investigated for Ge fractions between 0 and 0.56 over the temperature range of 770–920 °C. Si–Ge interdiffusivity is found to increase by 2.2× for every 10% increase in local Ge fraction for interdiffusion in strained Si/relaxed SiGe structures. Significantly enhanced Si–Ge interdiffusion is observed in structures with Si1−yGey layers under biaxial compressive strain. The interdiffusivity increases by 4.4× for every 0.42% increase in the magnitude of biaxial compressive strain. These results were incorporated into an interdiffusion model that successfully predicts the interdiffusion in epitaxial SiGe heterostructures.