A ceramic-based ITON piezoresistive pressure sensor with wide temperature range (RT-900 °C) and broad frequency response

Piezoresistive pressure sensors offer high accuracy, high sensitivity, and a compact form factor, making them widely adopted in aerospace applications. However, conventional designs are constrained by sensing materials and structural limitations, hindering pressure monitoring at temperatures exceeding 600 °C. Stable and repeatable pressure measurement over a wide temperature and frequency range remains a significant challenge. In this work, a ceramic-based nitrogen-doped ITO (ITON) piezoresistive pressure sensor is proposed. By utilizing an Al₂O₃ ceramic structure and ITO material, the issue of operational temperature limitations is effectively addressed, thereby enabling stable sensor output at high temperatures. Results show that the sensitivity of the sensor reaches 236 mV/mA/MPa at 900 °C. The linearity of the sensor is less than 3.74%FS in the range from 25 °C to 900 °C. The frequency response of the sensor exceeds 409 kHz across temperatures spanning 25 °C to 1000 °C, with an ultra-fast response time of 12µs. In addition, the resistance of the sensor chip increased by only 2.4% and 0.8% after being immersed in H₂SO₄ and NaOH solutions for 70 hours, respectively. Thus, the developed sensor demonstrates significant potential for pressure measurement in high-temperature and wide frequency domain environments.