Modeling and Characterizing Optical CMOS Sensors for Biomedical Low-Intensity Light Detection

In this work several photo-sensors include silicon PIN photodiode and avalanche photodiodes (SiAPDs) are addressed to develop a miniaturized near-infrared photo-sensor with high-sensitivity, low-power and low-noise characteristics using CMOS technology dedicated to biomedical imaging applications. These devices have been characterized and compared using different device simulators include COMSOL, TCAD, MATLAB, Crosslight-APSYS and Silvaco. The impact of simulation and reliability of the simulation results are evaluated by considering the measurement results. The sources of observed discrepancies between simulated and measured characteristics are discussed. Then a reliable technique to use device simulators and photo-sensor modeling results, is proposed based on our previous design, simulation and fabrication experiences. A new equivalent circuit model for SiAPD is also developed to be applied in circuit level simulations.