Abstract: With the rapid development of the telecommunications industry and microelectronics technologies, and with the increasingly clear development trend of fifth-generation (5G) communications, higher requirements have been placed on the performance of high-frequency miniaturized RF filters. The manufacture of BAW resonator filter is the most promising technology. Based on a large number of studies, this paper summarizes the preparation and optimization technologies of solidly mounted bulk acoustic resonator (SMR). Based on the technology of thin film roughness optimization, an AlN-ZnO co-resonating SMR was proposed to optimize the piezoelectric property and 〈0002〉 texture of ZnO film. The corresponding SMR is prepared and has achieved good device performance parameters. The series resonating Qs value is 616.2, the parallel resonating Qp value is 429.4, and the effect electromechanical coupling factor k2eff is 2.27%. This paper provides an innovative solution for the mass production of SMR.

Key words: solidly mounted bulk acoustic resonator (SMR), ZnO doped piezoelectric film, AlN-ZnO co-resonating layer, buffer layer