A new silicon biaxial decoupled resonant micro-accelerometer

In this paper, the design, the simulation, the fabrication and the experiment of a new silicon biaxial decoupled resonant micro-accelerometer are presented. The new biaxial resonant micro-accelerometer consisting of four identical tuning forking resonators, four pairs of decoupled beams, four lever mechanisms and a proof mass is decoupled by four pairs of decoupling beams in two sensitive directions, which will benefit to isolate the acceleration detections of the two axes. The simulation results prove that the proposed structure is able to decouple the planar 2-D acceleration into two independent acceleration components. And the two pairs of the decoupled resonator modes which are 23.893, 23.946 and 26.974, 26.999 kHz separately have a 3 kHz difference in frequency in order to suppress the mutual interference. Then the fabrication, the vacuum encapsulation and the design of oscillation loop and the frequency measurement circuit are illustrated. Experimental results show that the new biaxial decoupled resonant micro-accelerometer has good performance with the transverse sensitivity of 1.08 % in x-axis and 1.33 % in y-axis, the bias stability of 0.294 mg in x-axis and 0.278 mg in y-axis, and dynamic range of over 10 g, which proves that the new biaxial resonant micro-accelerometer is practicable and has an excellent decoupled performance.