Development of high-temperature piezoresistive pressure sensor based silicon on insulator

摘要

Silicon on insulator (SOI) substrate was prepared using ion implantation of oxygen technique. For piezoresistive detection, the top layer (0.2μm thick) silicon was used as an active material with the excellent single crystal siliconproperties. The structure of the pressure sensor chip was simulated and analyzed using the finite element method. Thepressure gauge chips were manufactured using MEMS techniques. The Si3N4 films were applied for the mask, and thesilicon cups were manufactured using KOH anisotropic wet etching process. Cr/Ni/Au multi-layers metal electrodeswere applied to guarantee the reliable work at high temperature. The manufactured sensors were measured with anapplied pressure of 0 to 6.0MPa at 300℃. The test results showed that the sensitivity was approximately 30mV/ (mA·MPa), the non-linearity was less than 1.5‰ FS, the repetition was less than 0.9‰FS. The research showed that theSOI piezoresistive pressure sensor could reliably work at a high temperature.