The effects of thermal nitridation on phosphorus diffusion in strained SiGe and SiGe:C

We investigated the thermal nitridation effects on phosphorus (P) diffusion in strained Si1−xGex and strained Si1−xGex:Cy with up to 18 % germanium and 0.09 % carbon. P diffusivities under thermal nitridation (vacancy injection) and effective inert condition were compared. The results show that thermal nitridation can retard P diffusion in SiGe, but the effectiveness of this retardation method decreases with the increasing Ge and C content. When 0.06 and 0.09 % carbon are present in Si0.82Ge0.18, thermal nitridation slightly increases P diffusivity compared to the inert condition. The Ge dependence can be explained by the increasing contribution from the vacancy-assisted mechanism for P diffusion in strained SiGe with the increasing Ge content. In terms of interstitial undersaturation ratio II∗\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \frac{\left[ I \right] }{{ \left[ I \right]^{*} }} $$\end{document} in Si0.82Ge0.18, thermal nitridation can further decrease II∗\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \frac{\left[ I \right] }{{ \left[ I \right]^{*} }} $$\end{document} by 31–53 % on top of the carbon effect.