Magnetoelectric GaN film bulk acoustic wave resonator

This paper presents a novel magnetoelectric GaN film bulk acoustic resonator (FBAR). The device integrates a 750 nm piezoelectric GaN layer with Molybdenum electrodes with a magnetostrictive Nickel layer, separated by 50 nm of silicon nitride. The FBAR is fabricated on a 1.2 × 1.2 mm ² GaN membrane released by micromachining of a high-resistivity silicon substrate. The device was placed in a cryostat (293 K, 10 ^-5 mBar) and measured in an external magnetic field. The magnetic influence on the amplitude of the S21 parameter at the operating frequency of 2.92 GHz showed values of 1521 ppm and 4123 ppm for an external magnetic field of 2850 Oe, in the case of out-of-plane and in-plane field orientation, respectively.