Enhancement of c-Axis Oriented Aluminum Nitride Films via Low Temperature DC Sputtering

In this study, we successfully deposit c-axis oriented aluminum nitride (AlN) piezoelectric films at low temperature (100 degrees C) via the DC sputtering method with tilt gun. The X-ray diffraction (XRD) observations prove that the deposited films have a c-axis preferred orientation. Effective d(33) value of the proposed films is 5.92 pm/V, which is better than most of the reported data using DC sputtering or other processing methods. It is found that the gun placed at 25 degrees helped the films to rearrange at low temperature and c-axis orientation AlN films were successfully grown at 100 degrees C. This temperature is much lower than the reported growing temperature. It means the piezoelectric films can be deposited at flexible substrate and the photoresist can be stable at this temperature. The cantilever beam type microelectromechanical systems (MEMS) piezoelectric accelerometers are then fabricated based on the proposed AlN films with a lift-off process. The results show that the responsivity of the proposed devices is 8.12 mV/g, and the resonance frequency is 460 Hz, which indicates they can be used for machine tools.

Automated summary

In this study, c-axis oriented aluminum nitride (AlN) piezoelectric films were successfully deposited at low temperature (100 degrees C) using the DC sputtering method with a tilt gun. The films exhibited superior piezoelectric performance compared to previous reported data. By rearranging the films at 25 degrees, c-axis orientation AlN films were successfully grown at 100 degrees C, which is much lower than previously reported growing temperatures.