PLL-Based Readout Circuit for SiC-MOS Capacitor Hydrogen Sensors in Industrial Environments

Abstract

For proper operation in real industrial conditions, gas sensors require readout circuits which offer accuracy, noise robustness, energy efficiency and portability. We present an innovative, dedicated readout circuit with a phase locked loop (PLL) architecture for SiC-MOS capacitor sensors. A hydrogen detection system using this circuit is designed, simulated, implemented and tested. The PLL converts the MOS nonlinear small-signal capacitance (affected by hydrogen) into an output voltage proportional to the detected gas concentration. Thus, the MOS sensing element is part of the PLL’s voltage-controlled oscillator. This block effectively provides a small AC signal (around 70 mV at 1 MHz) for the sensor and acquires its response. The correct operation of the proposed readout circuit is validated by simulations and experiments. Hydrogen measurements are performed for concentrations up to 1600 ppm. The PLL output exhibited voltage variations close to those discernable from experimental C-V curves, acquired with a semiconductor characterization system, for all investigated MOS sensor samples.

GAMMA IRRADIATION RESPONSE ON SiNWs BASED MOS CAPACITOR WITH HIGH-K Yb2O3 GATE DIELECTRIC

“…where ΔVfb is the shift in the flat band voltage prior to and after irradiation, while other parameters have already been defined in Equation (1). The value of ΔNit are found to be 2.11×10 11 cm -2 , 6.37×10 11 cm -2 and 6.22×10 11 cm -2 at 0Gy, 2Gy and 4Gy, respectively.…”

“…Metal oxide semiconductor (MOS) devices have attracted research interests from various research communities in the last decades and have been integrated them in various fields such as radiation sensors, electronic devices, and nanotechnology [1]- [3]. The existence of oxide layer in MOS devices makes them very sensitive to radiation.…”