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 off-current 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 data-line resistance and parasitic coupling. Details of the device design and fabrication, along with sensor performance characteristics, are presented and discussed. © 2008 Materials Research Society