Measurement of output voltage of aluminum nitride thin film as a pressure sensor at high temperature

The output voltage of sensor elements using AlN thin film was investigated at temperature up to 973 K with the frequency of 1 and 10 Hz under the stress of 200 ± 40 N, respectively, in nitrogen atmosphere. The output signals were ascertained at temperatures up to 937 K with both frequencies. The intensity of the output voltage before heating was 1.4–2.2 V approximately. It could be held close to the initial level up to 673 K, however, it declined over 773 K and came down to less than 10% of the original level at 873 and 973 K in the case of SUS 304 electrodes because of the degradation of stainless steel. In the case of Inconel 600 electrodes, it was approximately constant up to 873 K. However, the sample showed anomalously high output voltage of more than 13 V by the fluttering of the testing machine at 973 K. In spite of the exceeding condition, the elements responded the applied load. It is considered that a sensor element using AlN thin film can be applied as a pressure sensor at temperature up to 973 K.