Study on The Polar Orientation of Plasma-Deposited Piezoelectric Materials

This paper investigates the polar orientation of radio frequency (RF) sputtered piezoelectric materials. A theory was developed to explain deposited material polar orientation. Different impurities were added to the sputtering process to tune the aluminum nitride (AlN) polar orientation. By adding selected impurities, the AlN crystal orientation was improved and the process requirement relaxed, making the process possible on a wider range of toolsets. With the improved process, a low-stress, oriented AlN film was deposited with a low RF power (4.5 W/cm
²
).