Flexible Piezoelectric Sensors Using AlN Thin Films Prepared on Polyimide Films

Abstract

Oriented aluminum nitride (AlN) thin films have been directly prepared on polyimide (PI) films by rf magnetron sputtering. The AlN films have a wurtzite structure and consist of c-axis oriented columnar grains which have about 100 nm width. The insertion of sandwiching the AlN and polymer films between top and bottom electrodes, such as Pt/AlN/PI/Pt. Although AlN is a piezoelectric ceramics, the AlN films are flexible and excellent in mechanical shock resistance. The AlN films exhibit piezoelectric response in a wide temperature range from -196 to 300 ˚C, and can measure pressure within a wide range from pulse waves of hundreds Pa to 40 MPa.