Study On AlN Thin Film Bulk Acoustic Mass Sensor

As RF wireless communication technology and semiconductor Manufacturing Technology continue to progress in recent years. Development of mass sensor has become the focus of attention. Traditional mass sensors are becoming more and more miniaturized, integrated, intellectualized, informationzed. And the film bulk acoustic resonator (FBAR) technology-based micro-mass sensor are showing that the broad application prospects because of its small size, low loss, high sensitivity, high-quality factor, high frequency, temperature stability, low cost, compatibility with other semiconductor Arts advantage. Meanwhile, the research of FBAR sensors operate in liquid are of great importance in environmental monitoring, analytical chemistry, life sciences and other fields of epoch-making significance.This paper is to discuss FBAR mass sensor, mainly for preparation of AIN piezoelectric films, design FABR resonator and technology research, analysis of FBAR mass sensor performance and optimization. The main achievements and innovations include the following:1. Using RF magnetron sputtering prepared Optional C-axis oriented AIN thin films and C-axis inclined AIN thin films by changing the sputtering pressure, substrate temperature, nitrogen pressure conditions than the other parameters, The high-quality thin film can be prepared for FBAR sensor. C-axis inclined AIN films were deposited on Pt electrodes by method of two-step pressure. The films deposited by two-step pressure on Pt preferred as tilt columnar srystals with angle of5°when the two-step pressures are15-1.5Pa. In the process of the first high pressure step, the AIN films exhibit no preferred crystallite orientation. However, the growth of the second low pressure follows competition mechanism:the grains oriented with the same as flux grow faster than the other grains; as a result, the former oriented grains grow as inclined c-axis AIN films.2. Discussion on the Mo-Ti Bragg reflector roughness effected by substrate temperature Deposition of the interface is clear, smooth surface acoustic Bragg reflector, the preparation for the FBAR sensor basis. 3. Using semiconductor manufacturing processes in Mo and Pt electrodes were prepared on the SMR-type FBAR sensor, the device frequency response test results show that the Mo bottom electrode of the FBAR sensor for the resonant frequency is3.7GHz insertion loss is-43.9dB, with Pt as the bottom2.45GHz FBAR sensor electrode insertion loss-50dB, the last of the Mo bottom electrode of the FBAR sensor is calculated as the spirit of the sensitivity is1.554×106Hz·m2/ng.