Research Of FBAR Fabrication And Application

With the development of Microelectro-Mechanical Systems (MEMS) technology, the film bulk acoustic resonators (FBAR) have been used widely in industry in the last few years. Due to their excellent characteristics, such as small size, high operating frequency and low insertion loss (IL), FBARs based filters and duplexers have been successfully used in communication area. Furthermore, as FBARs work in a high frequency and have high Q(quality) factor, they also have been widely used in sensor field. Currently, FBARs based sensors for sensing physical parameters such as micro-mass, temperature, pressure and humidity have been reported. Although the applications of FBARs in sensing area are still under research, with the advancement of technology, we believe they will obtain extensively commercial success in sensor field in the coming future.The researching status of FBAR including FBAR working principle, structure, equivalent circuit models and manufacturing technology was firstly simply summarized this paper. Then the two manufacturing technology was elaborated, namly wet etching method and deep reactive ion etching (DRIE) method. And finally successfully manufacture the bulck silicon back etching FBAR in the laboratory.Process flow and layout were designed in the dissertation. It focuses on the RF reaction sputtering ZnO, deep reactive ion etching back cavity, ZnO via etching process, the electrode lift-off and the compatibility issues between each step, and connecting with the problems occured during the experiment to optimize the process and obtained the high yield of FBAR manufacturing process technology. At the same time, a new method of integrating FBAR signal processing chip with FBAR devices was proposed.In research of FBAR technology application, based on the analysis of FBAR model, a UV sensor FBAR and a new electric adjustable FBAR based on Schottky junction fused were proposed.(1) Testing the FBAR based on ZnO piezoelectric thin film as well as the characteristics under UV irradiation, summarizing the experimental data. Based on the mechanism analysis of experimental phenomena, the ultraviolet sensor device model was established by using ADS software simulation, simulation results prove the validity of the theories;(2)For FBAR based on ZnO thin film the DC bias voltage electric tested was done to get the FBAR under0to5V low voltage offset frequency changes characteristic, Schotty and FBAR coupled circuit model was established, ADS software simulation was done to verify the proposed model, then prediction of the direct current adjustable performance of FBAR was also proposed.