NanoDay 2021 – Poster 21 – Xu-Qian Zheng


Free-Standing Ferroelectric Hf0.5Zr0.5O2 Nanoelectromechanical Systems: Mechanical Property, Crystal Morphology and Energy Dissipation

Xu-Qian Zheng

Authors: Xu-Qian Zheng, Troy Tharpe, Philip Feng, Roozbeh Tabrizian

Faculty Mentor: Roozbeh Tabrizian, PhD

College: College of Engineering

Department: Electrical and Computer Engineering


Advances in creating polar structures in atomic-layered hafnia-zirconia (HfxZr1-xO2) films not only augurs extensive growth in studying ferroelectric nanoelectronics and neuromorphic devices, but also spurs opportunities for exploring novel integrated nanoelectromechanical systems (NEMS). Design and implementation of HfxZr1-xO2 NEMS transducers necessitates accurate knowledge of elastic and electromechanical properties. Up to now, all experimental approaches for extraction of morphological content, elastic, and electromechanical properties of HfxZr1-xO2 are based on solidly mounted structures, highly stressed films, and electroded architectures. Unlike HfxZr1-xO2 layers embedded in electronics, NEMS transducers require free-standing structures with highly contrasted mechanical boundaries and stress profile. Here we present a Hf0.5Zr0.5O2 nanoelectromechanical resonator for simultaneous extraction of Young’s modulus (320 GPa) and residual stress (577 MPa) in free-standing ferroelectric Hf0.5Zr0.5O2 films. Further, the evolution of morphology during creation of free-standing Hf0.5Zr0.5O2 structures is closely mapped using X-ray diffraction measurements, clearly showing transformation of ferroelectric orthorhombic to nonpolar monoclinic phase upon stress relaxation. Finally, mechanical dissipation pathways in Hf0.5Zr0.5O2 resonators, including air damping and thermoelastic damping, are carefully analyzed through quality factors from experimentally measured resonances using remote electrical field driving and optical interferometry detection.