Gamma Radiation Induced Effects on the Performance of Piezoresistive Pressure Sensors Fabricated Using Different Technologies

We have carried out experimental investigation of the effect of gamma radiation on the performance of piezoresistive pressure sensors realized using different fabrication processes. These processes included standard diffused piezoresistor process, silicon-on-insulator (SOI) wafer based process, and polysilicon piezoresistor based process. The pressure sensors were irradiated in a
⁶⁰
Co gamma chamber up to a total dose of 30 Mrad(Si). The sensors were characterized after different total dose exposures to measure the sensitivity, offset voltage, and hysteresis. All three types of sensors did not show failure up to the studied dose of 30 Mrad(Si). The sensors fabricated using diffused piezoresistor based and polysilicon piezoresistor based processes have shown insignificant change in the sensitivity. However, a significant change in the sensitivity (~13%) and offset voltage (~9%) was observed for the SOI wafer-based pressure sensor. The comparison of the gamma-induced degradation of three types of sensors shows that the polysilicon piezoresistor-based sensor has the best radiation hardness as it exhibits <;1% degradation of the sensitivity, offset voltage, and hysteresis for gamma radiation exposure of 30 Mrad(Si).