First Demonstration of High-Performance and Extremely Stable W-Doped In₂O₃ Gate-All-Around (GAA) Nanosheet FET

We demonstrate a gate-all-around (GAA) nanosheet FET featuring an atomic layer-deposited (ALD) tungsten (W)-doped indium oxide (In2O3), or indium tungsten oxide (IWO), channel. A novel channel release process is developed, utilizing wet etching with an etching selectivity exceeding 103 between the channel and a metal sacrificial layer (SL), enabling lithography-independent definition of the device channel length (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${L}_{\text {Ch}}$ </tex-math></inline-formula>). The fabricated nanosheet FETs, with scaled dimensions of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${L}_{\text {Ch}} =50$ </tex-math></inline-formula> nm and W<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text {Nanosheet}} =30$ </tex-math></inline-formula> nm, exhibit a high on-state current (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {ON}}$ </tex-math></inline-formula>) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$815~\mu $ </tex-math></inline-formula>A/<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>m at V<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text {DS}} =1$ </tex-math></inline-formula> V and V<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text {G}}-$ </tex-math></inline-formula> V<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text {T}} =3.5$ </tex-math></inline-formula> V, along with an ultralow off-state current (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {OFF}}$ </tex-math></inline-formula>) of 3 fA. These IWO-GAA nanosheet FETs are demonstrated to achieve exceptional threshold voltage stability under both positive (PBTI) and negative (NBTI) bias stress conditions, with the hero device achieving a record-low threshold voltage shift (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta \text {V}_{\text {T}}$ </tex-math></inline-formula>) of 88 mV for a stress voltage of V<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text {G}}-$ </tex-math></inline-formula> V<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text {T}} =2.6$ </tex-math></inline-formula> V, corresponding to a stress field (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${E}_{\text {Stress}}$ </tex-math></inline-formula>) of 5.4 MV/cm.