This paper reports the characterization and real-time testing of thin-film Pb(Zr0.52Ti0.48) (PZT) micro diaphragm pressure sensor at high temperature (up to 390 °C) and high pressure (up to 105 kPa) conditions. Firstly, the influence of thermal stress on micro diaphragm deformation is investigated theoretically and experimentally. Secondly, the effect of rhombohedral–tetragonal, tetragonal–cubic phase transitions and lattice parameter changes of the PZT composite on the resonance frequency are studied. Thirdly, a good performance of the proposed sensor at low-frequency oscillatory flow generated by a vibrating sphere source (frequency of 35 Hz) in silicone oil bath at different temperatures is reported. The observations lead to the conclusion that despite the fluctuations on resonant frequency with increasing temperature, the proposed PZT sensor can be effectively used in high temperature/pressure applications.

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This paper describes the development of a novel ruggedized high-temperature pressure sensor operating in lateral field exited (LFE) Lamb wave mode. The comb-like structure electrodes on top of aluminum nitride (AlN) were used to generate the wave. A membrane was fabricated on SOI wafer with a 10 µm thick device layer. The sensor chip was mounted on a pressure test package and pressure was applied to the backside of the membrane, with a range of 20–100 psi. The temperature coefficient of frequency (TCF) was experimentally measured in the temperature range of −50 °C to 300 °C. By using the modified Butterworth–van Dyke model, coupling coefficients and quality factor were extracted. Temperature-dependent Young's modulus of composite structure was determined using resonance frequency and sensor interdigital transducer (IDT) wavelength which is mainly dominated by an AlN layer. Absolute sensor phase noise was measured at resonance to estimate the sensor pressure and temperature sensitivity. This paper demonstrates an AlN-based pressure sensor which can operate in harsh environment such as oil and gas exploration, automobile and aeronautic applications.