Research On Integration Of FBAR Wireless Sensor

As semiconductor technology and RF communication technology continue to progress, traditional sensors are becoming more and more miniaturized, intelligentized, informationalized and cyberized step by step. Because of its high performance, low price, and good compatibility with standard CMOS process, FBAR has a large application potential. Integration of FBAR in CMOS process as well as application of FBAR in Wireless Sensor Networks has been a strong tendency. This paper mainly focuses on the issues of integration technology of FBAR wireless sensor. It includes 3 parts: FBAR's fabrication, integration process and modeling; FBAR wireless sensor application system design; tiny-mass sensor characteristics and sensing information processing chip. This work is meaningful for further research on integration of FBAR wireless sensor.Major work and innovation points of this dissertation are listed as follows:1. Optimization is made for FBAR design and fabrication process. A new structure and process that fabricate FBAR on the surface of CMOS circuit's passive layer is proposed. Several typical longitudinal-wave and shear-wave FBARs are designed, fabricated and tested. The paper analyzes the parasitics of FBAR, and put forward a new equivalent circuit model PMBVD which takes parasitics into account. This model could be used to improve the simulation accuracy of FBAR as well as to optimize the structure of FBAR's PADs.2. An in-depth analysis is made on FBAR tiny-mass sensor characteristics. Based on the analysis, we propose a dual-channel frequency difference counting method to acquire and process the information from FBAR tiny-mass sensor. This method is simple, reliable and accurate. Theoretically, it could detect the smallest mass of the FBAR's ability. An FBAR tiny-mass sensor signal acquisition and processing chip is designed, fabricated, and tested. Low-power source-coupled logic dividers are introduced to reduce the frequency of RF signals from Giga Hertz to a frequency that CMOS circuit could deal with.3. System architecture of FBAR wireless sensor unit is advanced. According to the analysis on this wireless communication links, we designed two CMOS Class E power amplifiers whose frequencies are 868MHz, 433MHz respectively. A low-power, low-noise FBAR oscillator with current-reuse cross-coupled configuration is presented, and temprature-compensation circuit is designed for FBAR oscillator.