Patent ID: 7470945
Filing Date: 2008-12-30
Classification: H01L

Abstract:
1. A CMOS image sensor, based on a substrate and comprising a transfer transistor, a reset transistor, a source follower transistor, a select transistor, a photodiode and a floating node structure, wherein the substrate comprises a floating node area between the transfer transistor and the reset transistor, and the floating node structure comprises: a P-well in the substrate within the floating node area; an N-well in the substrate outside of the floating node area; a lightly N-doped region, having a portion in the P-well and another portion extending out of the floating node area to connect with the N-well; a heavily N-doped region in the N-well; and a contact plug for coupling the heavily N-doped region to the source follower transistor, wherein the heavily N-doped region contacts a surface of the substrate.