Study of Relaxation of Strain in Patterned Structures using X-Ray Diffraction Technique

We investigate the strain state in patterned SiGe lines of various widths after strain relaxation by He ion implantation and annealing (Hollander et al, 2001). We expected that the relaxation in such patterned virtual substrates must be more pronounced in one direction of the stripe than the other, thereby opening a possibility for further enhancement of hole mobility. We employed high-resolution X-ray diffraction to study the relaxation of strain and to assess the structural quality of a series of SiGe striped samples with varying stripe widths from 0.82 to 100 mum, patterned in [110] direction on a (100) substrate. We see that the strain in the stripes in the two orthogonal directions is different i.e. the crystal structure of the stripes is orthorhombic