Broadband characterization of zinc oxide-based solidly mounted resonators

In recent years, a considerable amount of research has been conducted on thin film bulk acoustic wave (BAW) resonators in the area of RF microelectronics. They are attractive to the field because of their relatively small size and potential for fabrication on-chip. Several configurations are common, the solidly mounted resonator (SMR) being among them. Zinc oxide-based SMRs are fabricated with fundamental resonant frequencies near 1.9 GHz. Devices are grown on acoustic reflectors with different material pair combinations and comparisons are made between the characteristics of the resonators on each. Ballato's model is used to simulate the behavior of the device with excellent correlation across a broad frequency range. As a result, it is possible to extract various material parameters of both the piezoelectric layer and the films in the acoustic reflector via curve fitting techniques. The simulations are conducted using a SPICE-based software package in a Windows 98 environment.