A Nano-Mechanical Resonator with 10nm Hafnium-Zirconium Oxide Ferroelectric Transducer

This paper reports, for the first time, on a 10nm hafnium-zirconium oxide (Hf_0.5Zr_0.5O₂) (HZO) piezoelectric transducer for nano-electromechanical systems (NEMS). The super-thin HZO films are engineered through atomic-level stacking, capping with titanium nitride (TiN) electrodes, and proper thermo-mechanical treatment, to realize ferroelectric transducers with large piezoelectric properties. The developed 10nm transducer is used for excitation of a silicon-based multi-morph nano-mechanical resonator, with an overall thickness of ~350nm, at ~4MHz. The developed resonator, along with 120nm aluminum-nitride (AlN) transduced counterparts, are also used as test-vehicles to characterize ferroelectric and piezoelectric properties. Benefiting from large piezoelectric coefficient (e_31,HZO ≈ 2.3e_31AlN), fully conformal deposition, and CMOS-compatibility, ALD-deposited 10nm HZO transducer paves the way for realization of truly monolithic cm- and mm-wave RF front-ends for the emerging 5G wireless communication systems, and extreme/3D integration of NEMS sensors and actuators.