Method of fabricating radiation imager with single passivation dielectric for transistor and diode

A method of fabricating an imager array having a plurality of pixels, the method comprising, for pixel in the imager array, the steps of:

• forming a thin film transistor (TFT) body on a substrate up to the point of depositing a source-drain metal layer, said TFT body comprising a gate electrode, a gate dielectric material layer, a semiconductor material layer, and a doped semiconductor material layer disposed over said semiconductor material layer, the step of forming said TFT body further comprising removing the gate electrode material, said semiconductor material layer, and said doped semiconductor material layer from regions of said pixel other than the region in which said TFT body is disposed;
• depositing a source-drain metal layer over said TFT body and remaining portions of the pixel area, said source-drain metal layer being disposed on said gate dielectric layer in said remaining portions of said pixel area;
• forming a photosensor island on said source-drain metal layer, said photosensor island occupying portions of said pixel other than where said TFT is disposed, said source-drain metal layer being an etch protectant to protect said TFT body from etchants used in the formation of said photosensor island;
• and
• patterning said source-drain metal layer so as to form respective source and drain electrodes on said TFT body and associated contacts to said photosensor island and predetermined address lines, said source-drain metal layer comprising an uninterrupted metal layer between one of said source and drain electrodes and a bottom electrode of said photosensor island.