Employing Total Ionizing Dose Effect in PN-Junction Photodetectors Implemented in Standard CMOS Technology for Dosimetry Application

Radiation effects on electronic devices are usually considered as a significant source of degradation to the point where they can cause device failure. The effect of total ionizing dose, which is a permanent effect, affects the performance of electronic devices by changing their current or voltage characteristics. In photodetectors specifically, increasing the effect of total ionizing dose leads to higher dark currents. Although this negative radiation effect is avoided in designing, there are applications that potentially benefit from it. Radiation dosimetry is one of many applications in which the effect of radiation on devices is used for monitoring purposes. In this work, we present the feasibility of utilizing the total ionizing dose effect for radiation dosimetry. A PN-junction based photodetector implemented in 180 nm standard complementary-metal-oxide-semiconductor technology is simulated in Silvaco TCAD, and its dark current under different gamma-ray radiation up to 1 Mrad is studied. Oxide-trapped charges and interface states formed by the total ionizing dose effect induce more dark current, which is tabulated for different gamma-ray radiation doses up to 1 Mrad. A transimpedance amplifier – a picoammeter circuit – is integrated with the photodetector to monitor and measure different levels of radiation to demonstrate the conceptual design of the proposed dosimeter.