Photosensitive imager contact pad structure

A radiation imager comprising:

• a photosensor array disposed on a substrate;
• said photosensor array comprising a plurality of photosensor elements, each of said photosensor elements being coupled to a respective thin film transistor (TFT), said plurality of photosensor elements and respective TFTs being disposed in a matrix arrangement;
• each of said photosensors being fabricated with a plurality of materials, including a photosensor passivation material and an electrically conductive common electrode material;
• each of TFTs being fabricated with a plurality of materials, including an electrically conductive gate material, an electrically conductive source-drain material, and a TFT passivation material;
• said photosensor array further comprising a plurality of conductive address lines disposed in said array so as to respectively address each of said photosensor elements in said array, each of said address lines comprising a contact finger disposed outside a boundary of said matrix arrangement of photosensor elements to provide for electrical contact to components external to said photosensor array;
• each of said contact fingers terminating in a contact pad, each of said contact pads comprising materials also used in the fabrication of components in said photosensor array, each of said contact pads comprising a common electrode material upper layer and an underlying source and drain electrode (S-D) material layer, each of said contact pads further comprising a thin film transistor (TFT) passivation layer and a photosensor passivation layer disposed between portions of said common electrode material layer and said S-D material layer.