4H-SiC MEMS高温电容式压力敏感元件设计

Design of MEMS High-Temperature Capacitance Pressure Sensor Based on 4H-SiC

为了研制Si C高温电容式MEMS压力敏感元件以满足高温环境下压力参数测量,设计了一种基于P型4H-Si C减薄抛光工艺制备高温变间隙电容式压力传感器敏感元件结构方法;通过数值仿真,研究了敏感元件的性能,得到敏感元件输出电容随压力、温度的变化曲线;通过微机械加工工艺制备出了Si C电容式高温压力传感器敏感元件,研制出Si C电容式高温压力传感器原理样机,通过模拟高温压力传感器样机工作环境,搭建了高温微压测试平台并对原理样机进行性能测试;结果显示,样机在873.15 K下能够正常工作,灵敏度为18.7 f F/k Pa,非线性为12.60%,迟滞为0.47%,能够满足解调电路拾取压力信号.

A MEM capacitance pressure sensitive element based on wafer thinning process of P type 4H- SiC for high-temperature applications was presented and its performance was studied via numerical simu- lation. The output capacitance curves of the element versus pressure and temperature were obtained. The SiC capacitance pressure sensitive element was developed and fabricated with MEMS technology. Finally, the prototype sensor＇ s performance was tested by the calibration system, which was established to simu- late the sensor＇ s working environment. Test results indicate that the prototype sensor can work under 873.15 K, at which point the sensitivity of the sensor is 18.7 fF/kPa, the non-linearity is 12.60% and the hysteresis is 0. 47% , and the performance parameters are good enough for demodulation circuitry to pick up the pressure signal.