Implant damage and strain relaxation of embedded epitaxial silicon germanium layer on silicon

摘要

The authors report on the implant damage and strain relaxation in embedded silicon germanium (SiGe) layer, selectively grown on recessed silicon (Si) (001) with different recess length (defined as [110] direction, along the conventional Si transistor channel) and the same width (defined as [1-10] direction). Similar to the implant damage in blanket epi-SiGe layers on Si (001) reported previously, they observed two defect bands, one close to the surface and the other at SiGe/Si interface. Unlike the biaxial strain relaxation with misfit dislocations equally distributed along both the [110] and [1-10] directions in blanket epi-SiGe layers on Si (001), there is a gradual change from biaxial to uniaxial relaxation with misfit dislocations along only at the [ -10] direction and a decreasing density of misfit dislocation, with decreasing recess length.