Formation of a Ge-rich Si_1−x Ge _x (x > 0.9) fin epitaxial layer condensed by dry oxidation

Abstract

We have selectively grown an epitaxial Si 0.35 Ge 0.65 fin layer in a 65 nm oxide trench pattern array and formed a Ge-rich Si 1−x Ge x (x>0.9) fin layer with condensed Ge using dry oxidation. During oxidation of the SiGe fin structure, we found that the compressive strain of the condensed SiGe layer was increased by about 1.3% while Ge was efficiently condensed due to a twodimensional oxidation reaction. In this paper, we discussed in detail the diffusion during the twodimensional condensation reaction as well as the asymmetric biaxial strain of the SiGe fin before and after oxidation using a reciprocal space mapping measurement. The application of dry oxidation on selectively grown SiGe fin layer can be an effective method for increasing hole mobility of SiGe fin with increased Ge content and self-induced compressive strain.

Analysis of anisotropic in-plane strain behavior in condensed Si1−x Ge x fin epitaxial layer using X-ray reciprocal space mapping

“…In our previous study, we reported on the structure of a condensation Si 1−x Ge x fin that can efficiently increase the Ge content to >90% and simultaneously increase the anisotropic in-plane strain by dry oxidation of the Si 0.35 Ge 0.65 epitaxial fin layer. 28) In the oxidation of Si 1−x Ge x , the Si is selectively oxidized, while the Ge is rejected and piled up in a process referred to as Ge condensation. [29][30][31][32][33][34][35][36] The two-dimensional condensation of the Ge in Si 1−x Ge x fins forms a graded Ge content in the bottom of the condensed Si 1−x Ge x film as a result of interdiffusion during condensation; this bottom region acts as a graded strain relaxation buffer (SRB) for the condensed Si 1−x Ge x layer, thus increasing the asymmetric strain.…”