Highly Reliable Ferroelectric Hf0.5Zr0.5O2 Film with Al Nanoclusters Embedded by Novel Sub-Monolayer Doping Technique

Highly reliable ferroelectric (FE) Hf
_0.5
Zr
_0.5
O
₂
(HZO) film with Al nanoclusters embedded by sub-monolayer doping technique is demonstrated for the first time. Al nanoclusters increase the remnant polarization (Pr) and reduce the voltage necessary for polarization switching. Furthermore, the program and erase endurance at the cycle of more than 250k and the Pr retention at 85°C for 10 years are achieved. Al nanoclusters are formed by the partial oxidation of submonolayer metallic Al embedded in HZO films. Al nanoclusters enhance the large grain growth of orthorhombic-phase HZO during FE-HZO crystallization annealing. The reduction of grain boundaries caused by the large grain growth with Al nanoclusters effectively reduces the leakage current in the HZO film. As a result, reliability of the FE HZO film is significantly improved.