Effects of source/drain elevation and side spacer dielectric on drivability performance of non-abrupt ultra shallow junction gate underlap GAA MOSFETs

Present work focuses on quantitative effects of source/drain elevation height (hSD\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{h}}_{\text{SD}}$$\end{document}) and side spacer dielectric material (Air, SiO2, Si3N4 and HfO2) on the current drive of non-abrupt ultra shallow junction (USJ) gate all around (GAA) MOSFETs. It has been observed that the desirable unanimous reverse trend (increase in Ion\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{I}}_{\text{on}}$$\end{document} and decrease in Ioff\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{I}}_{\text{off}}$$\end{document} with increase in source/drain elevation height (hSD\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{h}}_{\text{SD}}$$\end{document}) and/or side spacer dielectric constant, εsp\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upvarepsilon_{\text{sp}}$$\end{document}). Utmost percentage improvement in Ion/Ioff\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{I}}_{\text{on}} /{\text{I}}_{\text{off}}$$\end{document} ratio at hSD=30.5nm\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{h}}_{\text{SD}} = 30.5\,{\text{nm}}$$\end{document} and σL=7nm\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sigma_{\text{L}} = 7\;{\text{nm}}$$\end{document} is found to be ~3000% for HfO2 while least as ~449% for Air with respect to their corresponding values at zero elevation. Thus, the increase in source/drain elevation with proper selection of side spacer is found to be a suitable approach. This will enhance the drivability as well as lower parasitic resistance in comparison to non elevated GAA MOSFETs at sub 20 nm technology node.