A high-resolution X-ray diffraction and transmission electron microscopic study was made of the mechanism of strain relaxation in GeSi layers which were grown onto low-temperature Si buffers. An analysis of X-ray rocking-curves showed that the strain relaxation of an alloy layer was quite inhomogeneous in its early stages, and became homogeneous when the layer became fully relaxed. High-resolution cross-sectional transmission electron microscopy indicated that stacking faults had formed in the low-temperature buffer near to the interface, and separated the mismatch dislocations in the interface into Shockley partials. It was proposed that this might be due to the aggregation of vacant defects in the low-temperature Si layer. The mechanism for this aggregation was the osmotic force which was created by the vacancy supersaturation in the low-temperature Si layer and/or the tension stress which propagated from the GeSi/Si interface.

The Formation of Dislocations in the Interface of GeSi/Low-Temperature Si Buffer Grown on Si(001). C.S.Peng, Y.K.Li, Q.Huang, J.M.Zhou: Journal of Crystal Growth, 2001, 227-228, 740-3