Experimental Examination of Relationship Between Polarization States and Piezoelectric Properties of SC0.3AL0.7N for Reconfigurable MEMS Devices

In this paper, for the first time, the dependency of elastic and piezoelectric properties on the polarization state of 30% Scandium-doped Aluminum Nitride <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\text{Sc}_{0.3}\text{Al}_{0.7}\mathrm{N})$</tex> thin-film is experimentally examined using a piezoelectric micromachined ultrasound transducer (PMUT) as the test vehicle. Intermediate polarization states are achieved by varying voltages and frequencies of the polarization switching pulses, and impedance plots of the PMUT under various polarization states were subsequently measured. By mapping the resonant frequency and effective coupling coefficient <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(keff^{2})$</tex> of the device with these polarization states, the impact of polarization on piezoelectric and elastic properties of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Sc}_{0.3}\text{Al}_{0.7}\mathrm{N}$</tex> film is revealed.