SiGe Coherent Islanding and Stress Relaxation in the High Mobility Regime

Real-time stress measurements during Si₈Ge₂/Si(001) heteroepitaxy, combined with ex situ microscopy, are used to examine islanding dynamics under conditions of relatively low strain and high adatom mobility, where morphological evolution bypasses dislocation formation. We show that growth in this regime proceeds similarly to growth of Ge/Si(001) (i.e., at high strain, low temperature), but with the length scales expanded by the reduced strain. This greatly facilitates measurement of the coupled kinetics of morphological evolution and stress relaxation.