High temperature pressure sensor using a thermostable electrode

High temperature pressure sensors have been widely applied in modern industry. However, the performance of the pressure sensor is largely dependent on the thermal stability of ohmic contact electrode. This paper presents a TiSi₂/Ti/TiN/Pt/Au multilayer electrode. Linear transmission line method (TLM) and voltmeter-ammeter method have been used to measure the electronic properties of the electrode at high temperature. The test results show that the multilayer electrode can be used in fabricating high temperature pressure sensor. Moreover, a high temperature piezoresistive pressure sensor is designed using this multilayer electrode. ANSYS software and finite element method (FEM) have been used to analyze the stress distribution, sensitivity and nonlinearity. To verify this design, the pressure sensor is fabricated based on silicon on insulator (SOI) wafer. The pressure sensor is measured across the range of 30-150kPa and the temperature range is 25-500°C. The test results show that the ohmic contact electrode and the pressure sensor are able to work at high temperature.