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We present an efficient simulation method for electronic transport and avalanche in single-photon avalanche diodes (SPAD). Carrier transport is simulated in the real space using a particle Monte Carlo approach based on the Fokker–Planck point of view on an advection-diffusion equation, that enables us to reproduce mobility models, including electric fields and doping dependencies. The avalanche process is computed thanks to impact ionization rates implemented using a modified Random Path Length algorithm. Both transport and impact ionization mechanisms are computed concurrently from a statistical point of view, which allows us to achieve a full multi-particle simulation. This method provides accurate simulation of transport and avalanche process suitable for realistic three-dimensional SPADs, including all relevant stochastic aspects of these devices, together with a huge reduction of the computational time required, compared to standard Monte Carlo methods for charge carrier transport. The efficiency of our method empowers the possibility to precisely evaluate SPADs figures of merit and to explore new features that were untrackable by conventional methods. An extensive series of comparisons with experimental data on state-of-the art SPADs shows a very good accuracy of the proposed approach.

Single Photon Avalanche Diodes (SPAD) are key optoelectronic detectors for medical imaging, camera ranging and automotive laser imaging detection and ranging (LiDAR) applications. Today, most of SPADs in the Time Of Flight (TOF) market are composed of a micrometric Silicon PN junction associated to a proximity CMOS electronics biasing the system above the breakdown voltage. These devices present low noise, high pixel-matrix integration capabilities, but their Photon Detection Efficiency (PDE) is relatively modest in the near infrared operating region (achieving typically only few percent at a wavelength of 940 nm). A considerable optimisation of the SPAD design is currently on going at an industrial level with a view of increasing the PDE without compromising the timing statistic response to avalanche (Jitter) and its quench probability. Within these perspectives, standard commercial Technology-Computer-Assisted-Design (TCAD) simulations can only provide a limited guidance for technological and design splits optimisation since they are based on deterministic solvers that are unable to capture these stochastic figures of merit. Since the seminal work from Spinelli [1] clearly showing that Monte Carlo simulations predictions can compare favourably with experimental measurements of PDE and timing resolution, the Monte Carlo method can be considered to be a useful one for the design of improved structures. It has been recently applied to optimize the PDE and Jitter of Silicon [3] and InGaAs SPADs [4],[5]. In this abstract we report a rigorous comparison between Monte Carlo predictions and measurements of PDE and Jitter. We also discuss in detail, the quench probability of these diodes once in avalanche. This latter point has rarely been discussed in literature and to the best of our knowledge never addressed within a Monte Carlo perspective.

International audience; Dark Count Rate (DCR) in Single-Photon Avalanche Diodes (SPAD) in Complementary Metal-Oxide Semiconductor technology is characterized and analyzed with a comprehensive simulation methodology. Based on a series of measurements of SPAD with various architectures, on an extended range of voltages and temperatures, the DCR measurements are correlated to the spatial localization of traps within the device and their parameters. To this aim, process and electrical simulations using Technology Computer-Aided Design (TCAD) tools are combined with an in-house McIntyre solver to compute the breakdown probability (Pt). The traps are accounted for using thermal SRH carrier generation-recombination mechanism which is coupled with the position-dependent breakdown probability. This rigorous methodology makes it possible to directly compare with DCR measurements, since only generated carriers with a non-negligible breakdown probability are considered

Traditional ghost imaging requires correlated but spatially separated photons and has been observed in many physical situations, spanning both the quantum and classical regimes. Here we observe ghost imaging in a new system—a system based on entanglement swapping, the key feature of a quantum network. We detail how the exact form of quantum interference between independent photons dictates the precise nature of the ghost imaging, for example, for an anti-symmetric projection, the recorded image is the contrast-reversed version of the object—where the object is bright, the image is dark, and vice versa. The results highlight the importance of state projection in this ghost-imaging process and provide a pathway for the teleportation of two-dimensional spatial states across a quantum network. Our results also indicate that ghost images with new image properties could be achieved in conventional settings through a variety of new signal processing procedures.