Micromachined PZT thin film actuators for micromotors
We fabricated and characterized a micromotor driven by a piezoelectric PZT (PbZrxTi1-xO3) thin films. Sputter and sol-gel techniques have been applied for the deposition of the PZT films onto a silicon stator membrane, which was 20 to 30 µm thick and had a diameter of 4 mm. The amplitudes of the membrane deflections are as large as 800 nm/V at the first resonance (26 kHz), and 60 nm/V at 1 Hz. The operation of the motor was obtained at 1 to 3 Vrms, with speeds of up to 200 rpm at 1.1 Vrms and torques of 35 nNm at 2.5 Vrms and 1mN force between rotor and stator. A long time test of 150 h showed no degradation of the motor performance.