Piezoelectric properties of sputtered AlN on silicon substrate

We report, for the first time, the measurement of the temperature dependence of the piezoelectric coefficient, d₃₃, of aluminum nitride sputtered on a silicon substrate under a high temperature of up to 300°C, and that d₃₃ shows the same value of 5 pC/N between 20°C and 300°C. A highly c-axis oriented aluminum nitride (AlN) film was successfully formed on polycrystalline silicon/silicon dioxide/silicon wafers by reactive sputtering to be a piezoelectric unimorph actuator. We directly measured the picometre level movement of the actuator at 20 kHz using scanning laser Doppler measurement at different temperatures.