Hafnium Oxide (HfO 2 ) - A Multifunctional Oxide: A Review on the Prospect and Challenges of Hafnium Oxide in Resistive Switching and Ferroelectric Memories.

Hafnium oxide (HfO 2 ) is one of the mature high-k dielectrics that has been standing strong in the memory arena over the last two decades. Its dielectric properties have been researched rigorously for the development of flash memory devices. In this review, the application of HfO 2 in two main emerging nonvolatile memory technologies is surveyed, namely resistive random access memory and ferroelectric memory. How the properties of HfO 2 equip the former to achieve superlative performance with high-speed reliable switching, excellent endurance, and retention is discussed. The parameters to control HfO 2 domains are further discussed, which can unleash the ferroelectric properties in memory applications. Finally, the prospect of HfO 2 materials in emerging applications, such as high-density memory and neuromorphic devices are examined, and the various challenges of HfO 2 -based resistive random access memory and ferroelectric memory devices are addressed with a future outlook.