High Fill Factor a-Si:H Sensor Arrays with Reduced Pixel Crosstalk

Abstract

In this paper, we report on low noise, high fill factor amorphous silicon (a-Si:H) image sensor structures for indirect radiography. Two types of the sensor arrays comprising n-i-p photodiodes and m-i-s photosensors have been fabricated. The device prototypes contain 100 x 100 pixels, with a pixel pitch of 139 µm. The active-matrix addressing is provided by low offcurrent TFTs. The sensors are vertically integrated onto the TFT-backplane, by implementing a 3-µm-thick low-k interlayer dielectric. This dielectric layer serves to reduce the data line capacitance and to planarize underlying topography. The detector was designed for reduced dataline resistance and parasitic coupling. Details of the device design and fabrication, along with sensor performance characteristics, are presented and discussed.