SiGe intermixing in Ge/Si(100) islands

We have applied atomic force microscopy and x-ray photoemission spectroscopy to the study of SiGe intermixing in Ge/Si(100) self-assembled islands. We have quantified the Ge/Si alloying as a function of the deposition temperature in the 500–850 °C range. The Si content inside the islands varies from 0% at 550 °C up to 72% at 850 °C. As a consequence of the reduction of the effective mismatch due to the observed SiGe intermixing, the critical base width for island nucleation increases from 25 nm for Tdep<600 °C up to 270 nm for Tdep=850 °C.