Negative Capacitance FET With 1.8-nm-Thick Zr-Doped HfO₂ Oxide

Abstract

We report on negative capacitance FETs (NCFETs) with a 1.8-nm-thick Zr-doped HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gate oxide layer fabricated on an FDSOI wafer. Hysteresis-free operation is demonstrated. When compared to a baseline that uses HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gate oxide with the same thickness, a subthreshold swing (SS) steeper by more than 20 mV/decade and larger than 10X reduction in the OFF current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{ \mathrm{OFF}}$ </tex-math></inline-formula> ) is observed at 30-nm channel length at constant <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{ \mathrm{\scriptscriptstyle ON}}$ </tex-math></inline-formula> . On the other hand, at matched <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I} _{ \mathrm{\scriptscriptstyle OFF}}$ </tex-math></inline-formula> , the NCFET provides a larger ON current at constant <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\mathrm {DD}}$ </tex-math></inline-formula> . Our results indicate that the beneficial characteristic offered by the NCFETs can be obtained at scaled channel lengths, while using oxide layers whose thickness is comparable to the high- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${K}$ </tex-math></inline-formula> oxide layer used in ultra-scaled nodes.