علي زارعي

This research presents a comprehensive framework for the modeling an‎d quantitative analysis of afterpulsing noise in Single-Photon Avalanche Diodes (SPADs) under the influence of neutron irradiation. Given the importance of the stable performance of these detectors in radiation-prone environments, such as space an‎d nuclear instrumentation, a precise predictive model is essential for designing radiation-hardened devices. To this end, a hybrid approach was employed. First, the structure of a SPAD based on 180 nm CMOS technology was accurately modeled using numerical TCAD simulations. Through this process, the key physical parameters of the device—including the breakdown voltage (approx. 22 V), the electric field distribution (max. 46.73 MV/m), an‎d the avalanche triggering probability for electrons an‎d holes—were extracted. These extracted parameters were then used as inputs for an advanced analytical model based on carrier trapping an‎d de-trapping (Trap-Detrap) processes, which was implemented in the MATLAB environment. The model successfully predicted the afterpulsing noise behavior in both pre- an‎d post-irradiation conditions. The pre-irradiation results showed an exponential decay of the noise with two distinct time components, demonstrating good agreement with experimental data. After applying neutron irradiation (with a fluence of 4.29×1010 n/cm2 at 10 MeV), the model predicted a 27% increase in afterpulsing probability, which aligns with reported experimental results. Furthermore, the analysis revealed that irradiation not only increases the noise amplitude but also complicates its temporal decay profile an‎d significantly heightens the dependence of afterpulsing probability on the excess bias voltage (Vex). In conclusion, this research provides a validated an‎d accurate modeling tool capable of quantitatively predicting the impact of neutron-induced damage on SPAD performance. This achievement can be directly utilized in the optimization an‎d design of the next generation of radiation-hardened detectors for critical applications.

ديود هاي بهمني تك فوتون , مدل سازي و شبيه سازي , احتمال پس پالس , تابش نوترون , اثرات تشعشع

single-photon avalanche diode(SPAD) , modeling an‎d simulation , afterpulsing Probability , neutron irradiation , TCAD , radiation effects , non-ionizing energy loss (NIEL)

Ali Zarei

Mohammad azim karami