Scandium aluminum nitride: Highly piezoelectric thin film for RF SAW devices in multi GHz range

Abstract

This paper describes the preparation, characterization and application of scandium doped aluminum nitride (ScAIN) thin film. First, ScAIN thin film is deposited using dual co-sputtering technique. The piezolectric coefficient d33 of the film increases as the scandium concentration in the film increases and reaches a value approximately five times larger than that of AIN. Next, the high temperature durability of the film is shown by the changelessness of piezoelectric coefficient after heat treatment of approximately 1,000°C. Then, surface acoustic wave (SAW) devices are fabricated using a ScAIN/6Hsilicon carbide (6H-SiC) structure, and it is shown that the structure offers large Vand K2, while possessing very small SAW attenuation even in the multi GHz range.