Demonstration of Tungsten-doped Indium Oxide MOSFETs with 3 Angstrom EOT, Improved Stability and High on-Current

This study demonstrates improved performance and reliability in back-end-of-line (BEOL)-compatible amorphous oxide semiconductor (AOS) MOSFETs. Employing Hf O2-ZrO2-HfO2 (HZH) laminated gate dielectric, we achieved a high on-state current <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathrm{I}_{\text{ON}})$</tex> of 244 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mu \mathrm{A}/\mu \mathrm{m}$</tex> for devices with a 50 nm channel length, operating at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{V}_{\text{OV}}=1.5\mathrm{V}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{v}_{\text{DS}}=1\mathrm{V}$</tex>. Crucially, these devices exhibited exceptional bias stress stability, with a minimal threshold voltage shift of only 10 mV under high stress of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{V}_{\text{stress}}=1\mathrm{V}$</tex>. The HZH gate stack enhanced charge confinement, minimized subgap density of states, and suppressed both positive and negative bias instabilities. This work establishes a new milestone for EOT scaling in BEOL-compatible AOS MOSFETs, paving the way for improved charge transport, enhanced stability, and the development of reliable 3D-integrated circuits.