Crosstalk and lateral conduction effects in continuous-sensor amorphous silicon imagers

Abstract

Studies are reported of the image-blur effects caused by lateral crosstalk between neighboring pixels of large-area amorphous silicon (a-Si:H) image sensors. Data are obtained from high fill factor sensor arrays using 512×512 pixels of 75 μm size and a pixel gap of 10 μm. Measurements of the line-spread function determine the charge transfer from the illuminated pixel to neighboring ones along both array orientations, and for different samples and operating conditions. The lateral conduction is attributed to three effects: conduction along the interface between the a-Si:H film and the underlying passivation; field-dependent electron injection at the edge of the sensor; and field enhancement of the interface conduction due to the bias applied to the address lines. We show that the crosstalk can be controlled by the choice of operating conditions and optimization of the materials.