2.4GHz射频薄膜体声波谐振器的研制

Study and fabrication of 2.4GHz RF film bulk acoustic resonator

提出了基于ZnO压电薄膜多层结构的2.4GHz射频薄膜体声波谐振器,并进行了研究。采用修正后的Mason等效电路模型对器件的谐振特性进行了分析和模拟。给出了采用MEMS工艺制备器件的工艺流程,并利用射频网络分析仪对实验器件进行了测试。利用多点数值拟合的方法消除射频测试中引入的寄生分布参数,提取出器件的实际参数:器件的串联谐振频率fs和并联谐振频率fp分别为2.3714GHz和2.3772GHz,相应的有效机电耦合系数为0.598%;串联谐振频率处和并联谐振频率处的Q值分别为500.3和425.5,f.Q值乘积达到1.2×1012。该谐振器器件的有效直径为200μm,样品实际尺寸为1.2mm×1.2mm×0.3mm,可用来制备体积小、高性能和低相噪的射频振荡器。

2.4GHz Film bulk acoustic resonator （FBAR） of multi -layer structure with ZnO piezoelectric film in - between was proposed and studied. The resonant properties of the FBAR were analyzed and simulated using the modified Mason equivalent circuit model. The fabrication processes of the FBAR samples were also given with MEMS micro - machining technologies. These FBAR samples were tested using the RF network analyzer. Data fitting method was used to remove the parasitic parameters and extract the real parameters of the tested samples. The measured Q - factors for series and parallel resonant frequencies at 2.3714GHz and 2.3772GHz are 500.3 and 425.5, respectively, and keff2 is 0.598%. Thef. Q of typical sample is about 1.2× 1012. With the die size of 1.2mm × 1.2mm × 0. 3mm （effective diameter about 200μm）, these FBAR resonators could be expected to be used in mini -size, high performance and low phase noise RF oscillators.