Communication-effects of DC-bias voltage on piezoelectric and dielectric properties of Li-doped ZnO thin film

Highly (002)-oriented 3 at% Li-doped zinc oxide (LZO) thin films are fabricated using a radio frequency magnetron sputtering technique with synchronous DC-bias voltages ranging from 0 ∼ 25 V. The DC-bias voltage modifies the microstructure and thickness uniformity of the films, and therefore changes their piezoelectric and dielectric properties. The optimal values of the effective piezoelectric coefficient (19.42 pm/V) and dielectric constant (17.75) are obtained using DC-bias voltages of 20 and 25 V, respectively. The superior piezoelectric performance is due to an improved crystallization of the LZO film, while the superior dielectric performance is owing to an improved thickness uniformity.