HIGH-RESOLUTION X-RAY-DIFFRACTION INVESTIGATIONS OF SI SIGE QUANTUM-WELL STRUCTURES AND SI/GE SHORT-PERIOD SUPERLATTICES/

Double crystal and triple axis X-ray diffractometry was used to charac terize the structural properties of Si/Si1-xGex multiquantum well samp les grown pseudomorphically on Si(001) substrates, as well as of short -period Si9Ge6 superlattices grown by molecular beam epitaxy on rather thick step-graded Si1-xGex (0 < x < 0.4, 650 nm thick) buffers follow ed by 550 nm Si0.6Ge0.4 layers. Reciprocal space maps around the (004) and (224) reciprocal lattice points yield direct information on the s train status of the layers in the heterostructure systems and in parti cular on the amount of strain relaxation.