Memory characteristics of atomic-layer-deposited high- κ HfAlO nanocrystal capacitors

The memory characteristics of atomic-layer-deposited high- κ HfAlO nanocrystals in a p-Si SiO2 [HfO2 Al2 O3] Al2 O3 /platinum structure have been investigated. After the annealing treatment, the high- κ HfAlO nanocrystals with a small diameter of <10 nm and high density of > 5× 1011 cm2 have been observed by high-resolution transmission electron microscopy. A large hysteresis memory window of ∼10.4 V has been obtained. The high- κ HfAlO nanocrystal memory capacitor with a small capacitance equivalent thickness of ∼8.5±0.5 nm shows a small leakage current density of ∼22 μA cm2 at a gate voltage of -16 V. A large memory window of ∼8 V has also been observed after 105 s of retention, due to the charge confinement in the high- κ HfAlO multilayer nanocrystals.