High-Performance Ce-Doped HfO2 Ferroelectric Thin Films by Atomic Layer Deposition

Abstract

Ce-doped HfO2 (HCO) ferroelectric thin films have attracted considerable attention for next-generation integrated ferroelectric devices owing to their excellent compatibility with complementary metal-oxide-semiconductor technology and promising ferroelectric properties. However, previously reported HCO films generally require relatively large thicknesses and high processing temperatures, limiting their application in highly scaled devices. Here, we demonstrate HCO ferroelectric thin films grown by atomic layer deposition (ALD) and systematically investigate the effects of Ce concentration and film thickness on their structural and ferroelectric properties. The HCO film with 5.0% Ce doping exhibits the highest ferroelectric orthorhombic phase fraction, which is attributed to the formation of coupled defects involving Ce-substitution on Hf sites and oxygen vacancies, as revealed by first-principles calculations. Moreover, the HCO films annealed at 700 °C exhibit excellent ferroelectric properties at the thickness ranging from 12 to 24 nm. In particular, the 18 nm-thick HCO film with 5.0% Ce achieves a remanent polarization of 19.4 μC/cm2 and an excellent switching endurance exceeding 1 × 109 cycles. These results demonstrate the potential of ALD-grown HCO as a scalable material platform for highly integrated and multifunctional ferroelectric devices.