High-k Hf-Based Nanocrystal Memory Capacitors with IrOx Metal Gate for NAND Application

Abstract

The memory characteristics of atomic layer deposited high-kappa Hf-based nanocrystals embedded in high-kappa 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> films in an n-Si/SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /high-k nanocrystal/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> /IrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> memory structure have been investigated. The high-k nanocrystals can be formed after high temperature (> 900degC) annealing process. The high-k nanocrystal memory devices with a small EOT of ~8 nm show a large hysteresis memory window of DeltaV ap 3.8 V at a sweeping gate voltage of plusmn9 V, 0.2 s. A hysteresis memory window of 0.9 V has also been observed under a small sweeping gate voltage of plusmn7 V. A good uniformity of the high-k nanocrystal memory devices is also observed. A large memory window of >2 V and a low charge loss of 14% are achieved after ~8 times 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> s (9 days) of retention time owing to the charge confinement in the high-k nanocrystals.