CMOS image sensor
AssigneeUnited Microelectronics Corp.
InventorChing-Hung Kao
Life of this patent
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Abstract
A CMOS image sensor is described, based on a substrate and including a transfer transistor, a reset transistor, a source follower transistor, a select transistor, a photodiode and a floating node structure. The substrate includes a floating node area between the transfer transistor and the reset transistor. The floating node structure includes a P-well in the substrate within the floating node area, an N-well in the substrate outside of the floating node region, a lightly N-doped region having a portion in the P-well and another portion connected 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.
Claims2
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 P-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;
- further comprising a P-doped region in a surface layer of the substrate in the floating node area.
Dependencies are inferred from the claim text.