Interdiffusion in strained Si/strained SiGe epitaxial heterostructures

摘要

The Si-Ge interdiffusivity in epitaxial strained Si/Si_(1-y)Ge_y/strained Si/relaxed Si_(1-x0)Ge_(x0) and strained Si/relaxed Si_(1-x0)Ge_(x0) heterostructures is investigated for Ge fractions between 0 and 0.56 over the temperature range of 770-920℃. Si-Ge interdiffusivity is found to increase by 2.2 x 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 Si_(1-y)Ge_y layers under biaxial compressive strain. The interdiffusivity increases by 4.4 x 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.