Simulation And Studying Of PMOS Radiation Sensors

The existence of space radiation environment could damage the device, so it is important that monitor the radiation doses real-time. A variety of factors affect the radiation sensitivity, stability, accuracy of PMOS radiation sensors, including the device structure, process conditions, applied electric field, etc.According to the two different models of oxide charge for PMOS radiation sensors after irradiation, and calculation results show that the model that satisfied first-order kinetic equation is agree with the experiment datas well, and can be applied to a wider range of radiation does, then create a single gate PMOS radiation sensor model considering total dose effects, then calculation and analyze the impacts of the relevant parameters including the gate oxide thickness, channel doping concentration on threshold voltage shifts. The results show that gate oxide thickness is a major factor to induce the threshold voltage shift. In addition, MEDICI software simulate and analyzes the other factors to affect the radiation effects of a single dielectric gate PMOS radiation sensors, the results show that total dose, bias conditions, dose rate, temperature, annealing, and other factors have effect on the sensitivity of PMOS radiation sensors. On positive bias conditions, the threshold voltage shifts of single dielectric gate PMOS radiation sensor is largest, and the sensitivity is highest;the lower the dose rate, the larger threshold voltage shifts with the same total dose; the interface trap charge formed in the Si/SiO₂ will compound through thermally or tunneling electron for single dielectric gate PMOS radiation sensor, that result in the occurrence of annealing and affect the measurement accuracy.Study and simulate the radiation effects for the dual dielectric gate PMOS radiation sensors, the result show that the sensitivity is higher than the single dielectric gate PMOS radiation sensors, and the dose rate dependence is small, almost no annealing, the stability and accuracy of irradiation is better than the single dielectric gate PMOS radiation sensors under negative bias conditions.For the new SOI PMOS radiation sensors, this paper mainly simulation and study the electric field distribution, the potential distribution, the oxide charge of buried oxide layer after irradiation under different bias conditions, and the effects of channel length, buried oxide layer thickness, dose rate, and so on. The result show that the threshold voltage shift is the largest, the sensitivity is higher under PG bias; the shorter channel, the greater threshold voltage shifts; the thicker buried oxide, the greater threshold voltage shifts; dose rate little impact, almost no annealing.This paper mainly analyzes the radiation characteristics under the different conditions for different PMOS radiation sensors by using MEDICI software, that could be reference analysis for the design of high sensitivity, high stability, a wider measuring range of PMOS radiation sensors.