Relaxation of strained pseudomorphic Six Ge1-x layers on He-implanted Si/δ-Si:C/Si (100) substrates

Abstract

In this letter we present a method to increase the efficiency of SiGe layer relaxation by He+ ion implantation and annealing. Preferential nucleation of He platelets along a δ -impurity layer grown in the Si substrate below the SiGe layer results in planar localization and homogenization of dislocation loop sources inducing a more uniform distribution of misfit dislocations. We demonstrate this for a thin Si:C layer grown by reduced pressure chemical vapor deposition. The optimization of the conditions for efficient relaxation and layer quality is studied with respect to the position of the Si:C layer and the process parameters. Relaxation degrees up to 85% are obtained for Si0.77 Ge0.23 layers. © 2009 American Institute of Physics.