Second-order Nonlinearity of Amorphous SiOF Films in FBARs

In this study, the impact of SiOF on the 2nd harmonic (H2) of TC-FBAR was investigated. TC-FBARs with SiOFs as temperature compensation material on the outside of the electrodes were fabricated, and their H2 were measured. The measured H2 were very different from that of the standard FBAR consisting of electrodes and piezoelectric AlN, and it is confirmed that the SiOF has a strong impact on the H2 of the TC-FBAR. As a result of comparing the simulated H2 with the measured H2, we confirmed the existence of the strong second-order nonlinearity in elasticity in SiOF.