Simulation and test of a novel SOI high temperature pressure sensor

A novel high temperature pressure sensor is designed by the authors. It is based on a SOI construction, replacing the traditional pn junction insulation with SiO₂ insulation. The dielectric isolation guarantees low leakage current at high temperature. Thus, the sensors could be used in a high temperature environment. In this paper, a series of SOI high temperature sensors were simulated and analyzed by ANSYS software. The influence of thickness and length-width ratio of the strain diaphragm on the theoretical output was discussed. Accordingly, an optimal design of the strain diaphragm was presented and the location of the piezoresistors was determined. Finally, the sensors were fabricated according to the layout, and then tested. The test results showed that the actual measurement values are consistent with the simulation. The output voltage keeps good linearity with input pressure even at high temperatures. The properties of the product are satisfactory.