Simulation of Single Particle Displacement Damage in Silicon – Part I: Global Approach and Primary Interaction Simulation

A comprehensive approach is developed for the simulation of Single Particle Displacement Damage in silicon, from the incident particle interaction in silicon, to the resulting electrical effect observed experimentally. The different steps of the global approach are described. The paper then focuses on the first step corresponding to Monte Carlo simulation of the primary interaction. The characteristics of the Primary Knock-On Atom (PKA) generated by neutron- or proton-silicon interactions for different energies are explored, analyzing in particular the PKA range in energies and species. This leads to the selection of 1 and 10 keV silicon atoms as good candidates to best represent the displacement cascades generated by all PKA. These PKA characteristics will be used as input in the following Molecular Dynamics simulation step, developed in a separate paper to simulate the displacement cascade generation and evolution. Monte Carlo simulations are also performed in a geometry representative of an image sensor, analyzing the distribution of non-ionizing deposited energy. The obtained distributions appear very similar for incident neutrons from 3 to 18 MeV and incident protons of 200 MeV, in agreement with similarities observed in experimentally measured dark current distributions in image sensors. The effect of geometric parameters on these distributions is finally explored

Modeling Approach for the Prediction of Transient and Permanent Degradations of Image Sensors in Complex Radiation Environments

A modeling approach is proposed to predict the transient and permanent degradation of image sensors in complex radiation environments. The example of the OMEGA facility is used throughout the paper. A first Geant4 simulation allows the modeling of the radiation environment (particles, energies, timing) at various locations in the facility. The image sensor degradation is then calculated for this particular environment. The permanent degradation, i.e. dark current increase, is first calculated using an analytical model from the literature. Additional experimental validations of this model are also presented. The transient degradation, i.e. distribution of perturbed pixels, is finally simulated with Geant4 and validated in comparison with experimental data

Dark Current Random Telegraph Signals in Solid-State Image Sensors

This paper focuses on the Dark Current-Random Telegraph Signal (DC-RTS) in solid-state image sensors. The DCRTS is investigated in several bulk materials, for different surface interfaces and for different trench isolation interfaces. The main parameter used to characterize the DC-RTS is the transition maximum amplitude which seems to be the most appropriate for studying the phenomenon and identifying its origin. Proton, neutron and Co-60 Gamma-ray irradiations are used to study DC-RTS induced by both Total Ionizing Dose (TID) and Displacement damage (Dd) dose. Conclusions are drawn by analyzing the correlation between the exponential slope of the transition maximum amplitude histogram and the location of the DC-RTS-induced defects. The presented results can be extrapolated to predict DC-RTS distributions in various kinds of solid state image sensors

Radiation Effects in CCD on CMOS Devices: First Analysis of TID and DDD Effects

As CMOS image sensors become more and more attractive and with high performances, it becomes possible to use CCD on CMOS devices with reasonable lengths. However, no study has been done on the radiation hardness of such CCD on CMOS devices. Therefore, we propose in this paper a first study of Charge Transfer Inefficiency (CTI) and dark current degradation under TID and DDD irradiations. To do so, test chips have been processed in conventional deep submicron CMOS imaging technologies, and characterized before and after irradiations

Dark Current Spectroscopy in neutron, proton and ion irradiated CMOS Image Sensors

The dark current spectroscopy is tested on twenty CMOS image sensors irradiated with protons, neutrons and various ions at different energies. The aim of this work is to differentiate the effect of coulomb and nuclear interactions on the radiation-induced dark current distribution and to identify the main radiation-induced defects responsible for the dark current increase for each type of interaction. For low-energy protons and low-energy light ions (which produce well-separated low energy coulomb interactions), we find that most of the pixels belong to a quantized dark current spectrum at low dark current. In these pixels, the dark current increase seems mainly dominated by specific point defects such as the divacancy and the vacancy-phosphorus complex. Thus, these simple defects seem to form when the displacement damage is rather low and sparse. On the contrary, for nuclear interactions (with neutrons or high-energy protons) producing high coulomb NIEL silicon PKAs or for low energy heavy ions (also having high coulomb NIEL), the DCS spectrum is not visible and all the pixels belong to an exponential hot pixel tail which extends to very high dark current. In these pixels, the dark current increase is mainly dominated by defects with close-to-midgap energy levels. These defects seem more complex than point defects because they can have many different generation rates (explaining the smooth hot pixel tail) and because they tend to form when the displacement damage is high and dense

Dark Current Spectroscopy on Alpha Irradiated Pinned Photodiode CMOS Image Sensors

Dark Current Spectroscopy (DCS) is tested for the first time on irradiated Pinned PhohoDiode (PPD) CMOS Image sensors (CIS) to detect and identify radiation-induced silicon bulk defects in the depleted volume of the pixels. Two different CIS are tested: a 5MP Commercial-Off-The-Shelf (COTS) CIS from OmniVision (OV5647) and a 256x256 pixels custom CIS. These CISs are irradiated with alpha particles at various fluences and two different particle energies are tested on the custom CIS (4 MeV and < 500 keV). Several types of defects are detected in both CIS (up to five defects in the custom CIS). The dark current is measured at various temperatures to extract the activation energy and deduce the energy levels of the defects. The defect formation rate per unit fluence is calculated. In the custom CIS, the annealing behavior of the defects is also studied by performing an isochronal annealing. Two different defects are identified: the divacancy and the vacancy-phosphorus. This work proves that the DCS technique can be used on irradiated CIS to detect and identify radiation-induced defects in silicon

Validation of a model for Dark Current Non Uniformity generated by Displacement Damage Dose in irradiated CMOS Image Sensors

Validation of a model for Dark Current Non Uniformity generated by Displacement Damage Dose in irradiated CMOS Image Sensors

Investigations on the vulnerability of advanced CMOS technologies to MGy dose environments

This paper investigates the TID sensitivity of silicon-based technologies at several MGy irradiation doses to evaluate their potential for high TID-hardened circuits. Such circuits will be used in several specific applications suc as safety systems of current or future nuclear power plants considering various radiation environments including normal and accidental operating conditions, high energy physics instruments, fusion experiments or deep space missions. Various device designs implemented in well established bulk silicon and Partially Depleted SOI technologies are studied here up to 3 MGy. Furthermore, new insights are given on the vulnerability of more advanced technologies including planar Fully Depleted SOI and multiple-gate SOI transistors at such high dose. Potential of tested technologies are compared and discussed for stand-alone integrated circuits

Hardening approach to use CMOS image sensors for fusion by inertial confinement diagnostics

A hardening method is proposed to enable the use of CMOS image sensors for Fusion by Inertial Confinement Diagnostics. The mitigation technique improves their radiation tolerance using a reset mode implemented in the device. The results obtained evidence a reduction of more than 70% in the number of transient white pixels induced in the pixel array by the mixed neutron and γ-ray pulsed radiation environment

Dark Current Spectroscopy in neutron, proton and ion irradiated CMOS Image Sensors: from Point Defects to Clusters

The dark current spectroscopy is tested on twenty CMOS image sensors irradiated with protons, neutrons and various ions at different energies. The aim of this work is to differentiate the effect of coulomb and nuclear interactions on the radiation-induced dark current distribution and to identify the main radiation-induced defects responsible for the dark current increase for each type of interaction. For low-energy protons and low-energy light ions (which produce well-separated low energy coulomb interactions), we find that most of the pixels belong to a quantized dark current spectrum at low dark current. In these pixels, the dark current increase seems mainly dominated by specific point defects such as the divacancy and the vacancy-phosphorus complex. Thus, these simple defects seem to form when the displacement damage is rather low and sparse. On the contrary, for nuclear interactions (with neutrons or high-energy protons) producing high coulomb NIEL silicon PKAs or for low energy heavy ions (also having high coulomb NIEL), the DCS spectrum is not visible and all the pixels belong to an exponential hot pixel tail which extends to very high dark current. In these pixels, the dark current increase is mainly dominated by defects with close-to-midgap energy levels. These defects seem more complex than point defects because they can have many different generation rates (explaining the smooth hot pixel tail) and because they tend to form when the displacement damage is high and dense