Characterization of a Temperature-Sensitive Nano Piezoelectric Mechanical Resonator With a 20nm Free-Standing Hf0.5Zr0.5O2 Membrane

We studied the temperature effects on the resonant frequency of nano piezoelectric mechanical resonators based on Hf0.5Zr0.5O2 thin films. Two square-shaped resonators of 30 $\mu$ m and 50 $\mu$ m in length were fabricated and tested, having a resonant frequency of 225.8 kHz and 98.5 kHz, respectively. The temperature coefficient of frequency (TCF) of the devices was characterized in the range from −20 °C to 147 °C. Both devices exhibited a positive TCF around 83.6 ppm/°C to 105 ppm/°C in the range from 30 °C to 147 °C, which may result from the combined effect of thermal expansion mismatch between the materials and the temperature coefficient of Young’s modulus of the HZO material. Moreover, the 50 $\mu$ m device shows a negative TCF around −110 ppm/°C to −99.9 ppm/°C within the range from −20 °C to 30 °C, which may be due to stress relaxation during the heating process. These results underscore the significance of HZO material in nanoscale piezoelectric resonator applications and lay the foundation for our future work aimed at developing nanoscale piezoelectric devices based on HZO. [2024-0040]