Line Width Dependence of Anisotropic Strain State in SiGe Films Induced by Selective Ion Implantation

We investigated the line width dependence of anisotropic strain states in SiGe layers grown on selectively ion-implanted Si substrates with stripe patterns. It was found that strain relaxation of the SiGe layers on the unimplanted region occurred only along the stripe pattern and that the increase in the ion-implanted region provided larger anisotropy of the strain state. From the observation of one-directional surface steps, it was concluded that the uniaxially strained SiGe layer was formed by plastic deformation caused by selective misfit dislocation generation, which means that the anisotropic strain induced in the SiGe film is stable and good for device applications.