High-$\kappa$ and Metal-Gate pMOSFETs on GeOI Obtained by Ge Enrichment: Analysis of ON and OFF Performances

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> For the first time, we report high-<formula formulatype="inline"><tex>$\kappa$</tex> </formula>/metal-gate pMOSFETs fabricated on high-quality 200-mm germanium-on-insulator (GeOI) wafers obtained by the Ge enrichment technique. The highest mobility peak (200 <formula formulatype="inline"><tex>$\hbox{cm}^{2}/\hbox{V}\cdot\hbox{s}$ </tex> </formula>) and driving current (<formula formulatype="inline"><tex>$I_{\rm ON}\! = \!\hbox{115}\ \mu\hbox{A}/ \mu\hbox{m}$</tex></formula> at <formula formulatype="inline"><tex>$V_{G}\! - \!V_{\rm th}\! = \!-\hbox{0.8}\ \hbox{V}$</tex> </formula> and <formula formulatype="inline"><tex>$V_{\rm DS}\! = \!-\hbox{1.2}\ \hbox{V}$</tex></formula>, for <formula formulatype="inline"><tex>$L = \hbox{0.5}\ \mu\hbox{m}$</tex></formula>) have been demonstrated for GeOI <formula formulatype="inline"> <tex>$\hbox{HfO}_{2}/\hbox{TiN}$</tex></formula> pMOSFETs on Ge layers as thin as 50 nm. As compared to silicon-on-insulator control devices, 2<formula formulatype="inline"><tex>$ \times$</tex></formula> enhancement of peak mobility has been achieved. Due to temperature variation experiments and technology computer-aided design simulations, we have investigated the key physical phenomena responsible for the measured <emphasis emphasistype="smcaps">OFF</emphasis> currents (band-to-band tunneling at high <formula formulatype="inline"><tex>$V_{\rm DS}$</tex></formula> and generation–recombination via the Shockley–Read–Hall process at low <formula formulatype="inline"><tex>$V_{\rm DS}$</tex></formula>). </para>