Ultrathin HfON Trapping Layer for Charge-Trap Memory Made by Atomic Layer Deposition

Abstract

Charge storage characteristics of a hafnium oxynitride (HfON) charge-trapping layer prepared by atomic layer deposition in a metal-Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> -HfON-SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -Si (MAH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</sub> OS) structure are investigated. We found that an ultrathin HfON (~2.5 nm) embedded in MAH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</sub> OS has large memory window (~7.5 V at V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</sub> = ±15 V), sufficient erase speed (Δ V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FB</sub> = 4 V at -16 V/1 ms), and satisfactory data retention. From the relation of erase transient current density (J) versus tunnel oxide e-field (E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TUN</sub> ), we also found that the erase mechanism of MAH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</sub> OS depends on electron detrapping from HfON to Si substrates. However, MAH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</sub> OS embedding with a thicker HfON shows a poor data retention due to the increase of crystallization of the trapping layer.