Enhanced remnant polarization in ferroelectric Hf0.5Zr0.5O2 thin film capacitors through Mo top electrode by post-metallization annealing treatment

Abstract

Zr-doped HfO2 (Hf0.5Zr0.5O2) ferroelectric thin films have garnered considerable attention due to their appealing attributes, including a large bandgap (>5 eV), low crystallization temperature, and compatibility with CMOS technology. In this study, we present the achievement of a substantial remnant polarization in ferroelectric Hf0.5Zr0.5O2 thin films, fabricated through atomic layer deposition, with Mo and TiN serving as the top and bottom electrodes, respectively. The Mo/Hf0.5Zr0.5O2/TiN capacitor exhibited commendable ferroelectric behavior and demonstrated high endurance within a thermal budget ranging from 400 to 500 °C. Leveraging the relatively low thermal expansion coefficient of the Mo top electrode facilitated the induction of in-plane tensile strain, fostering an increased formation of the ferroelectric orthorhombic phase within the Hf0.5Zr0.5O2 layer. Elevating the post-metallization annealing temperature to 500 °C yielded a substantial increase in 2Pr (≈54 μC/cm2) with excellent endurance exceeding 106 cycles. The influence of annealing temperature on the morphological and structural properties of Hf0.5Zr0.5O2 thin films was comprehensively analyzed through atomic force microscopy and grazing incidence X-ray diffraction analysis.