Deposition of highly c-axis-oriented ScAlN thin films by RF magnetron sputtering using a Sc-Al alloy target

High-Sc-content ScAlN thin films have attracted significant attention because of their strong piezoelectricity. Instead of a co-sputtering system, a conventional RF-magnetron sputtering system was employed using a Sc-Al alloy metal target for deposition of ScAlN thin films. Highly c-axis-oriented ScAlN thin films with a Sc concentration of 32 at.% were obtained. We also demonstrate that a one-port surface acoustic wave (SAW) resonator based on the ScAlN/Si structure has a K
²
value of 1.7% at 2 GHz, which is four times larger than that of the AlN/Si structure.