A 4H–SiC Vibration Sensor With the Working Temperature up to 600 ^∘C

High-temperature vibration sensors are critical in extreme environments such as aerospace, automotive, power generation, where common sensors fail due to excessive heat. This study introduces a vibration sensor that can withstand high temperatures up to 600^◦C based on the piezoresistive effect of N-type 4H-SiC. The sensor chip was designed by theoretical modeling and multiphysics simulation, and fabricated by combining micro-electronmechanical systems (MEMSs) technology and femtosecond laser etching. The sensor performance was extensively verified from 25^◦Cto 600^◦C. The sensitivity of the sensor decreases from 0.153 mV/g at 25^◦C to 0.105 mV/g at 600^◦C with a temperature coefficient of −0.054% FS/°C at 600^◦C. The sensor’s sensitivity decreases essentially linearly with increasing temperature. Dynamic tests showed the sensor’s usable frequency is 0–590 Hz and the resonant frequency is 1179.85 Hz at 25^◦C while decreasing to 1156.76 Hz at 600^◦C. The designed sensor showed the reliability of high impact resistance up to 225% overload and random vibration. These findings suggest that the designed vibration sensor can be a promising alternative for high-temperature vibration monitoring.