Effect of Sc Concentration on the Memory Window in Al_1-xSc_xN/Two-Dimensional Channel Ferroelectric Field-Effect Transistors

Recently, the integration of a scandium-doped aluminum nitride (Al<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</inf>Sc<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf>N) dielectric layer with a two-dimensional (2D) channel has attracted significant attention in ferroelectric field-effect transistors (FeFETs). The effect of Sc doping concentrations (x) on the memory window (MW) in FeFETs with a 100 nm Al<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</inf>Sc<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf>N dielectric layer and a 2D MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> channel is investigated using the technology computer-aided design (TCAD) simulations. Simulation results show that the MW increases from 34.23 V to 39.08 V with increasing <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$x$</tex> from 0.27 to 0.36, and then decreases to 31.07 V as <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$x$</tex> further increases to 0.43. Furthermore, the MW gradually becomes symmetrical at about a gate voltage of 0 V as <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$x$</tex> increases from 0.27 to 0.43. These variations in the MW are mainly attributed to the decrease of coercive field (Ec) with increasing x, which will enhance the switching of ferroelectric polarization. This work offers valuable insights into optimizing the MW for Al<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</inf>Sc<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf>N FeFETs.