Excellent Endurance (> 10¹³) of Charge Trap Memory Based on H_xWO₃ Charge Trap Layer With Shallow Trap Level Using Hydrogen Spillover

In this study, we present an IGZO-based volatile charge trap memory, employing a hydrogenated WO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>(H<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub>WO<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{3}}\text {)}$ </tex-math></inline-formula> charge trap layer (CTL) with shallow traps. To overcome the interfacial issues in conventional Si-based transistors, we utilized the IGZO transistor to facilitate fast charge trapping / de-trapping within the CTL without barrier. Furthermore, through the hydrogen spillover with chemical reaction, we engineered the trap level and density in WO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> based CTL to achieve the shallow trap levels. Consequently, for the shallow trap level, high hydrogen concentration (>10%) was realized in the CTL owing to low activation energy with hydrogen spillover. In addition, both experimental results and Density Functional Theory simulations confirmed that hydrogen interstitial defects (H<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\text {i}}\text {)}$ </tex-math></inline-formula> could serve as shallow traps (<0.1 eV) in the H<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub>WO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> CTL when the hydrogen concentration exceeded 10% in the WO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> bulk. Finally, the synergy effect between the IGZO transistor and H<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{0}.{18}}$ </tex-math></inline-formula> WO<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> CTL enabled low voltage operation (<2 V), fast switching speed (<10 ns), highly stable endurance (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\gt 10^{{13}}$ </tex-math></inline-formula> cycles), large sensing margin (>3 V), multi-bit operation (3 bit), and excellent retention (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim ~20$ </tex-math></inline-formula> s).