First Demonstration of High-Performance and Extremely Stable W-Doped In₂O₃ Gate-All-Around (GAA) Nanosheet FET
Eknath Sarkar, Chengyang Zhang, Dyutimoy Chakraborty, Sharadindu Gopal Kirtania, Khandker Akif Aabrar, Hyeonwoo Park, Jaewon Shin, Hyun Jae Lee, Mengkun Tian, Asif Islam Khan, Shimeng Yu, Suman Datta
Abstract
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.