2-DIMENSIONAL IMAGE SENSORS BASED ON AMORPHOUS-SILICON ALLOY P-I-N-DIODES

Two-dimensional amorphous silicon alloy image sensors have been develo ped. We have built a demonstration device on a 9x9cm(2) area, having a 500 mu m pixel pitch. The pixel is based on a TCO-p-i-n-i-p-Metal str ucture. The p-i-n photodiodes (PD) are the photo-sensing elements and are stacked and back-to-back connected to n-i-p blocking diodes (BD), which perform the addressing and the connection of the PDs to a data b us. Due to an optimization of the thickness and of the energy gap of t he a-Si:H layers, we obtained a rectification ratio I-f/I-r approximat e to 10(4) between the current levels in forward (I-f) and reverse (I- r) bias conditions, under 1001ux green illumination. The binary detect ion of a light level has been performed at a scanning rate of 5.4 Mpix el/sec.