Patent ID: 7288429

Claim:
A method for forming an image sensor with a vertically integrated thin-film photodiode, comprising: providing a substrate; forming an interconnection structure adjacent to the substrate, wherein the interconnection structure includes a top metal layer comprising a plurality of first metal pads for thin-film photodiodes and a second metal pad for a ground pad; forming a dielectric layer on the interconnection structure; forming a plurality of first openings and a second opening in the dielectric layer; forming a layer doped with a first conductive type conformally on the dielectric layer and in the first and second openings; coating an organic spin-on material on the layer doped with the first conductive type with a substantially flat plane; removing the organic spin-on material and the layer doped with the first conductive type until the upper surface of the dielectric layer is exposed, wherein the dielectric layer, and upper surfaces of the organic spin-on material and the layer doped with the first conductive type in the first and second openings together form a substantially planar surface; removing the remaining organic spin-on material to form a plurality of bottom doped layers with the first conductive type in the first openings and the second opening, wherein each bottom doped layer contacts the corresponding first metal pad without extending outside the surface of the corresponding first metal pad; forming a stacked layer of an I-type layer and an upper doped layer with a second conductive type over at least one bottom doped layer and the dielectric layer; removing the bottom doped layer in the second opening; and forming a transparent electrode over the upper doped layer and contacting the second metal pad through the second opening in the dielectric layer.