Design, Modeling, and Characterization of a Floating Gate Dosimeter in Standard CMOS Technology for Sensor Reuse

This article presents the design, model, and characterization of a floating gate dosimeter (FGDOS), fabricated using standard complementary metal-oxide-semiconductor (CMOS) technology. The proposed model incorporates a parameter to account for trapped charge on the oxide, thereby providing deeper physical insight into the device’s behavior. We present a comprehensive comparison between the proposed model and experimental data, validating the accuracy of the proposed model. In addition, we propose a characterization method to extract key parameters of the FGDOS. Experimental validation was conducted using a 6 MeV linear accelerator and an X-ray diffractometer, with results demonstrating the model’s accuracy across a dose range of over 100 Gy (H₂O). Finally, we show that, after each reset of the floating gate (FG), the dose can be determined from a normalized sensitivity, which is independent of the previous history of the sensor. This means that the FGDOS can be reused several times and still keep the same dependence of the normalized sensitivity on the dose.