X-ray reciprocal space mapping studies of strain relaxation in thin SiGe layers (<= 100 nm) using a low temperature growth step

Relaxation of thin SiGe layers (similar to 90 nm) grown by molecular beam e pitaxy using a low temperature growth step (120-200 degreesC) has been inve stigated using two-dimensional reciprocal space mapping of X-ray diffractio n. The samples studied have bt en divided in two groups, depending on the s ubstrate cooling process during the growth of the low temperature layer. II has been found that a higher degree of relaxation was easily achieved for the sample group without growth interruption. A process window for full rel axation of the Si0.74Ge0.26 layer has been observed in the range of 140-150 degreesC. (C) 2001 Elsevier Science B.V. All rights reserved.