HRTEM STUDY OF SI1-XGEX

Epitaxial Si1-xGex (0 less than or equal to x less than or equal to 1) multilayers, grown on Si(001) at 350 degrees C using a hot-wire assis ted gas source molecular beam epitaxy, were observed by HRTEM. Two sam ple preparation techniques are compared: Ar+ ion milling and tripod th inning, It is shown that the first one gives rise to an important crys talline reorganization whereas the second one provides a large cross-s ection suitable for HRTEM investigations, We focused our studies on tw o kinds of interfaces: Ge-Si and Si-Ge. It appears that the Si layer s upports the main relaxation, resulting in a high density of stacking f aults which allows the growth of a clean Ge upperlayer.