High-Temperature SiC Piezoresistive Accelerometer Fabricated by Femtosecond Laser

High-temperature accelerometers are in high demand as the industry develops. SiC has broad application prospects in the field of high-temperature accelerometers due to its excellent mechanical and electrical properties. However, the inefficient processing methods severely limit the development of SiC sensing devices. This article proposes a 4H-SiC piezoresistive accelerometer and its fabrication method combining femtosecond laser and MEMS processing technology. Femtosecond laser was adopted to reduce the thickness of the cantilever and release the proof mass of accelerometer, overcoming the SiC deep etching problem. The designed accelerometer was tested. The sensitivity of the designed sensor is 0.0763 mV/g/5V, which can be used for low-g vibration tests. The resonant frequency of the sensor is 1145 Hz. The high-temperature performance of the sensor was verified. The sensitivity of the sensor is 0.0529 mV/g/5V at 250 °C, with a sensitivity temperature coefficient of -0.12% FSO/°C and a zero-offset temperature coefficient of -1.38% FSO/°C. The research verifies the feasibility of the femtosecond laser etching SiC accelerometer and the high-temperature working ability of the SiC accelerometer.