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 I D 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. (c) 2006 Elsevier B.V. All rights reserved.