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 degreesC range. The Si content inside the islands varies from 0% at 550 degreesC up to 72% at 850 degreesC. 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 T-dep< 600 degreesC up to 270 nm for T-dep=850 degreesC. (C) 2001 American Institute of Physics.