Modeling and Analysis of a SiC Microstructure-Based Capacitive Micro-Accelerometer

Abstract

In this study, a comb-type capacitive accelerometer based on a silicon carbide (SiC) microstructure is presented and investigated by the finite element method (FEM). It has the advantages of low weight, small volume, and low cross-coupling. Compared with silicon(111) accelerometers with the same structure, it has a higher natural frequency. When the accelerometer vibrates, its resistive force consists of two main components: a viscous damping and an elastic damping force. It was found that viscous damping dominates at low frequency, and elastic damping dominates at high frequency. The second-order linear system of the accelerometer was analyzed in the time-frequency domain, and its dynamic characteristics were best when the gap between the capacitive plates was 1.23 μm. The range of this accelerometer was 0–100 g, which is 1.64 times that of a silicon(111) accelerometer with the same structure. In addition, the accelerometer could work normally at temperatures of up to 1200 °C, which is much higher than the working temperatures of silicon devices. Therefore, the proposed accelerometer showed superior performance compared to conventional silicon-based sensors for inertial measurements.

Study on the Dynamic Characteristics of a SiC-Based Capacitive Micro-Accelerometer in Rarefied Air

“…, the analytical expressions of the viscous damping force 0 F and elastic damping force 1 F of the rectangular plate can be derived [21]:…”

“…The gap distance between the movable electrode plate and the fixed electrode plate is 1.23 µm. When the displacement of the movable plate is h = h 1 cos(ωt), the analytical expressions of the viscous damping force F 0 and elastic damping force F 1 of the rectangular plate can be derived [21]:…”

“…In [21], we designed a capacitive micro-accelerometer based on a silicon carbide microstructure by the finite element method (FEM). The physical model and the process flow of the accelerometer are shown in Figure 1, and the optimized structural parameters are listed in Table 1.…”

A MEMS All‐SiC Accelerometer and its Application in Vibration Test of Aero‐Engine†

“…Finally, most of the current studies on SiC -based accelerometers are still in the stage of structural design, performance simulation, and exploration of some key processes. There are not enough test results, parameters of the material and the performance data of the sensors for Refs [11,12]. This is mainly due to the lack of efficient and reliable processing methods to achieve all SiC -based accelerometer, resulting in a lack of sensor products that can be tested.…”