Solidly mounted resonators with layer-transferred AlN using sacrificial crystalline surfaces

A new process to manufacture solidly mounted bulk acoustic wave resonators using wafer bonding and sacrificial surface removal is introduced. With this process, AlN thin films are obtained having excellent c-axis orientation with XRD rocking curve FWHM of 1.36deg and material electromechanical coupling constant of 6.8% exceeding the epitaxial AlN electromechanical coupling constant. The resonators are working around 2.35 GHz and have Q-values as high as ~1300.