Spice model for a laser scanned photodiode tricolor image sensor

A SPICE model of the three color a-SiC:H/a-Si:H p–i–n/p–i–n detector operation is presented. The equivalent electric circuit able to describe the behavior of the multilayer structure under non-uniform illumination is composed of two series connected diodes, representing the p–i–n structures, with two non-linear current sources in parallel, representing the photogeneration for different steady-state RGB illumination, with their values depending on the light penetration depth and intensity of the impinging light. This device represents the 1D model of the Laser Scanned Photodiode and may be interconnected in a 2D array trough resistors, modeling the high resistivity of the a-SiC:H layers. Electrical simulations were performed for different illumination conditions, and they are compared with the experimental data. The influence of the electrical model parameters on sensor characteristics is analyzed. A physical model supported by the electrical simulation gives insight into the methodology used for image representation and color discrimination.