A 30-nm thick integrated hafnium zirconium oxide nano-electro-mechanical membrane resonator

Abstract

This paper reports a 30 nm-thick integrated nano-electro-mechanical resonator based on atomically engineered ferroelectric hafnium zirconium oxide (Hf0.5Zr0.5O2) film. A 10 nm-thick Hf0.5Zr0.5O2 layer is atomically engineered through capping with 10 nm-thick titanium nitride (TiN) layer and rapid thermal annealing to promote the orthorhombic crystal phase with strong ferroelectric properties. The resulting metal-ferroelectric-metal (MFM) membrane is then patterned to create an integrated nano-electro-mechanical resonator with an overall thickness of 30 nm and a planar-to-vertical aspect ratio exceeding 104:1. Benefiting from large electrostrictive effects in ferroelectric Hf0.5Zr0.5O2, the 30 nm-thick nanomechanical resonator is excited into flexural resonance at 195 kHz with a very large vibration amplitude of ∼100 nm. The transmission response of the nano-electro-mechanical resonator is extracted, using a two-port apodization of the TiN electrodes, showing quality factors (Q) of 15 and 3300 at atmospheric and 10−7 Torr ambient pressures, respectively. Finally, the structural robustness of the MFM nano-membrane is explored through the application of a ∼24 μm deflection, using a point-force by a micro-probe, highlighting the extended elasticity despite the small thickness and ultra-high aspect ratio. The atomic-level thickness, fully integrated operation, high Q, and structural robustness of the Hf0.5Zr0.5O2-based nano-membrane resonator promise its potential for the realization of highly integrated transducers for chip-scale classical and quantum information processing and sensing applications.

Review on the Microstructure of Ferroelectric Hafnium Oxides

“…Several such realizations have been shown in literature, particularly for bulk acoustic resonantors for high‐frequency filter applications. Hereby, both resonating membranes [ 190,191 ] as well as fins, have been demonstrated. [ 192 ] The latter again exploits the property of HfO 2 to be conformally deposited by ALD processes.…”

High Quality Factors in Superlattice Ferroelectric Hf0.5Zr0.5O2 Nanoelectromechanical Resonators

“…2,13,14 This unique dimensional scalability is not only pivotal for the realization of dense memory devices on advanced CMOS nodes but also highly favorable for the creation of high-performance nanoelectromechanical systems (NEMS). 11,12,15 Ultrascaled hafnia-zirconia piezoelectric transducers, with thicknesses of just a few nanometers, favor the creation of integrated NEMS sensors with enhanced detection limits. 16−18 Furthermore, the extreme thickness scalability, while sustaining piezoelectricity, augurs the promising potential of hafniazirconia to create integrated high-quality-factor (Q) NEMS resonators.…”

“…This is highly desirable for the realization of modern wireless communication systems that target the use of wide cm and mm wave spectrum to fulfill the massive data rate and ultralowlatency requirements of emerging applications such as metaverse, connected vehicles, internet of things, etc. 11,12,21 Realization of high-performance hafnia-zirconia NEMS resonators requires quantitative understanding of the govern- ing energy dissipation mechanisms limiting Q. Such understanding is not trivial, considering the complex crystal structures of hafnia-zirconia with the coexistence of multiple phases and strong dependence of morphology and energy dynamics on mechanical boundary conditions.…”

“…The observation of ferroelectricity in hafnia-zirconia, over a limited thickness range and once subjected to proper thermomechanical treatments, provides the unprecedented opportunity of having a multifunctional material in advanced semiconductor nodes. Over the past decade, nanoscale ferroelectric hafnia-zirconia films have been developed and explored for diverse applications, including ultralow-power memory and computing, − energy harvesting and storage, , and sensing and actuation. − …”

Aging in Ferroelectric Si‐Doped Hafnium Oxide Thin Films

“…Other ferroelectrics lose their spontaneous polarization in the nm regime. [1] However, the ferroelectric properties have been researched intensively for nonvolatile memories, [2] the piezoelectric, [3,4] and pyroelectric [5,6] properties begin to receive attention only recently. The sizable pyroelectric and piezoelectric coefficients, semiconductor-compatible manufacturing, and high scalability make HfO 2 interesting for prospective sensor applications and nanoelectromechanical system integration.…”